I have taken the ideas of J-man and placed them here.  I have made a couple of additions, such as the "Write" skill includes the ability to read.  I mean, how can you write if you can't read? I have also re-formatted it slightly. I have combined all of the ideas from the various authors.  I found it too tedious to give every single idea the credit due to the author.  This page will be edited, etc. to death.  Besides, the various authors will see their ideas and recognise them. :)  Exception goes to Lord Irish for the complete GW Skills System 02!

Use any of these systems which fit your gaming style!

There will STILL be NO CLASSES! Your character will still do whatever he/she wants without "Class" limitations!  Classes make everyone the same!  Characters are individuals, as unique in his/her own way as each of us are.  Besides, I think that Classes are what the Created do!  Example: A Communication received from controlling AI to production center: "This sector requires an additional 10 Enforcer units and 23 Scout units..."  Then the production center cranks-out the androids and programs them with the required skills....
This is too limiting.  It also sets a "D&D" mentality to the setting:  You can automatically tell what "class" a person is when you look at him!   Example: You walk into an Inn and see a group of people sitting a a table.
1 person is in robes (obvious Wizard/Magic User),
3 people wear chainmail armor (obvious Fighters),
1 person wears leather armor (Thief), etc..
However, the Class-Specific skills WILL be added!  Your character could take 1 skill from the "Enforcer" class, 1 from Esper, etc..

Conversely, it makes no sense to have a Grav Vehicle driving skill on a Tech I chart.  So what we should do first is gather together all the possible skills we'd want, then sort them by tech level.  Sure, there is bound to be some crossover, but we should be able to come up with a system that more accurately reflects the society that spawned it.

I like the idea of having skills broken down by tech level, but shouldn't there be a way to learn skills from different tech levels?  In order to learn a new skill from a higher tech level, you have to have a teacher from that tech level.  This means that a Tech level I character has to travel to a Tech level III town or city to be able to learn a Tech level III skill!  Then, he has to find someone willing to teach that skill....As a character gains experience points, he/she can apply them to other skill tables to learn additional skills.

Also, obvious, to learn skills of higher tech levels, a character would have to travel to an area where that tech level of skill was available.  The burden to make this all plausible should be on the GM of a particular campaign.  He (or she) would need to provide enclaves, towns, cities, etc. as potential destinations for the adventurers.  If a character finished an adventure in a tech 1 village and had gained experience points enough to increase his  skills, he couldn't suddenly learn how to drive an ancient vehicle, or read ancient writings, etc without a teacher or material to study.  Any character that was anxious to learn new skills would willingly travel to another location or take on another task to get him to a location where he can improve himself.  This should make a GM's job easy, at least as far as motivating his players is concerned.

As for initial skill picks (call them basic skills) I was thinking of using like IQ/3 to determine how many initial basic skills a character may either pick or roll from the basic skills chart.

 For Example, a Tech I villager :

 His IQ is, say 14.  14/3 gives us 4 picks (drop the fraction).  His chart may look like this :

Fishing - The ability to fish and know the best places for fishing.

Weaving/Sewing - The ability to use one's manipulative appendages in order to make various items such as blankets, baskets, etc.

Tracking/Hunting - The ability to track game or enemies with little or no clues; the ability to hunt animals for food efficiently.

Woodworking - Able to make implements out of wood of superior craftsmanship.

Herbs/Salves - Knows which herbs to use for a given reason, how to find them and use them, how to make healing salves and medicines.

Horse - Husbandry, riding, etc.  Able to breed horses for desired abilities; able to ride well.

Farming - knows the proper seasons for planting, how to get the best crops, etc.

Writing - Ability to read/write and become literate.

Weapons - Character may choose a single weapon each time this is chosen for a proficiency in it's use.

Skill- 0 (anyone starts with this until they select a proficiency) =  -1 to-hit adjustment; unfamiliar with weapon and it's proper use.
Skill- 1 = 0 adjustment to-hit.  Familiar with weapon and knows how to use it properly.
Skill- 2 = +1 to-hit.  Very familiar with weapon and comfortable in using it in most conditions.
Skill- 3 = +2 to-hit.  Extremely familiar with weapon, comfortable using it in any condition.  considered an 'expert'.
Skill- 4 = +3 to-hit.  This person is considered a "Master" in this weapon.

Cooking - able to cook and prepare foods for consumption (real cooking, not just roasting it over a fire).

Trading - able to barter well with others.

Or, really simple to use, just make all skill roles using the characters intelligence divided by 3 as your base number,and as each character completes game sessions award skill points based on thier use of skills,the better they play the more points they earn,but never more than 3 per game to keep balance.

This takes a little more time in creation but it works out well and skills can be learned for different tech levels.
Use SJgames compendium for the best list of skills.

Of course, this will require you to buy it... :)

 Skills are areas of expertise.  All skills are represented by a title (the name of the skill itself), a related attribute (a character attribute which is most closely associated with the skill in question), and an expertise rating (number) which indicates how well a character performs the skill.
 All characters have a base skill rating in any given skill equal to one-third of its related attribute, rounded down, plus his or her expertise rating.  Whenever a character attempts a skill check, this number or less must be rolled on d20 for the skill check to succeed.

 For example, Jorgreff the Barbarian has a DEX: 13 and Climbing (Dex): 4, meaning that Jorgreff  must roll an 8 or less on d20 to successfully scale a wall or cliff (13/3=4.33, rounded down to 4, plus 4 equals 8).  The GM has the right to modify the skill check as he or she sees fit.
For example, a wall made of solid Teflon might incur a -6 skill penalty, with the result that the same character above would only succeed in scaling it on a roll of 1 or 2!

 NOTE:  Skill checks come into play in unusual or significant situations.
 Characters should not have to make skill checks in completely frivolous or mundane scenes.
For example, a character wouldn’t need to make a Climbing skill check if he or she were trying to reach the top of a low hill, or even if trying to pass through mountainous foothills under the expert tutelage of a veteran mountain climber.  On the other hand, if the PC were trying to reach the top of a low hill while being pursued by an Ark hunting party, or were racing across the same mountainous foothills while being pursued by the
 Knights of Genetic Purity, one or more Climbing skill checks would be totally appropriate.

 No skill rating may exceed 12.  Consequently, even the most well-trained, naturally adept character will fail a skill roll sometimes (on a roll of 19 or 20).  However, because the possibility exists for characters who can
 never fail a skill check by the numbers to enter the game, a roll of 20 on any given skill check automatically fails.  On the other hand, this is just a game, so a roll of 1 on any given skill check automatically succeeds, even
 if the PC has absolutely no idea what he or she is doing.

 All characters enter the game with a number of skills equal to their INT.
 This number is further adjusted as follows:

 ·       +2 skills if the character is a Pure Strain Human
 ·       +0 skills if the character is a Humanoid
 ·       -2 skills if the character is a Mutated Animal
 ·       -3 skills if the character is a Mutated Plant

 Once the player chooses his characters skills, he or she rolls 1d4 for each of them.  The result is the character’s initial expertise rating in that particular skill.

 As an integral part of character development, skills don’t come cheap.  The cost of improving a skill is equal to 1,000 XP times his or her current expertise rating in a given skill, plus 1,000 times the expertise rating the
 character is trying to obtain.  A character cannot raise a skill level’s expertise rating by more than 1 over the course of any given play session.

 For example, Jorgreff the Barbarian wants to raise his Climbing expertise rating from 4 to 5.  This will cost him 9,000 XP (4 x 1,000 XP for his current expertise rating, plus 5 x 1,000 XP for his target expertise rating).  Although Jorgreff has 50,000 XP to spend, he may not increase his expertise rating in Climbing above 5 during this play session; he must wait for the next game to raise it to 6, and the following session to raise it to 7, and so on, despite the fact that he has more than enough experience points to pay for such an increase right now.

 A character may improve an unlimited number of skills during the course of any given play session, so long as none of them are improved by more than a single point.

 A number of skills have a prerequisite, that is, another skill or attribute value that must be obtained before a character can acquire a given skill.
 Many of these prerequisites pertain to a skill’s Tech Level.  For any given skill with one or more prerequisite skills, the character must possess the prerequisite skills with an expertise rating of 1 or more.

 For example, Jorgreff the Barbarian wants to acquire the Jury Rig, Tech Level IV skill, giving him the ability to juryrig Tech Level IV hardware and software.  Jorgreff does not possess any Jury Rig skills.  To obtain the Jury Rig IV, Tech Level IV skill, Jorgreff would have to purchase Jury Rig I, II, and III with an expertise rating of 1 first.  In sum, Jorgreff would have to spend a minimum of 4,000 XP over the course of 4 play sessions to acquire Jury Rig, Tech Level IV with an expertise rating  of 1 (Jury Rig I, II, and III at expertise rating 1 would cost 1,000 XP each, and would have to be acquired one game session at a time, followed by the purchase of Jury Rig, Tech Level IV at an expertise level of 1, which would also cost 1,000 XP).

 NOTE:  Characters do not “inheret” expertise ratings from the same skill at different Tech Levels.  If Jorgreff the Barbarian has Jury Rig, Tech Level IV:  9, but only acquired Jury Rig, Tech Level I, II, III at expertise level 1 to eliminate his prerequisites, he may well be adept at jury-rigging Tech Level IV hardware and software, but a complete novice at jury-rigging older hardware and software.  For a real-world analogy, consider computer programmers who are experts in Visual Basic or Java, but who have never worked with COBOL, Perl, or C++; these people may be able to create an interactive Web site based on the latest, greatest tools, but couldn’t create a Guest Book based on CGI if their lives depended on it!  They might be able to understand the gist of what they’re seeing, but could hardly be considered experts.

That having been said, We've changed Our system a bit, and hopefully for the better. Why are We posting this to the Gamma World 5th edition list, then?
 Well, you wouldn't have GW5 without GW1-4, and maybe someone on this list will find a use for what We've come up with.

 Please note that what follows is a work in progress, and We're still working on the individual skill descriptions...
 

SKILLS
Skills are areas of expertise. All skills are represented by a title (the name of the skill itself), a related attribute (a character attribute which is most closely associated with the skill in question), and an expertise rating (number) which indicates how well a character performs the skill.
 All characters have a base skill rating equal to one-third of its related attribute, rounded down, plus his or her expertise rating. Whenever a character attempts a make use of a skill, the player or GM roles d20 and adds the difficulty rating, per p. 70 of the Gamma World 4th ed. Rules. If the total is less than or equal to the character’s expertise rating plus one-third of his or her related attribute, the skill check has succeeded.

 For example, Jorgreff the Barbarian has a DEX: 13 and Climbing (Dex): 4, meaning that Jorgreff (or the GM) must roll an 8 or less on d20 to successfully scale a wall or cliff (13/3=4.33, rounded down to 4, plus 4 equals 8). This also assumes that the task was Easy (+0 difficulty rating).
 The GM has the right to modify the skill check as he or she sees fit. For example, a wall made of solid Teflon might incur a +10 skill penalty, with
 the result that the same character above would only succeed in scaling it on a roll of 1 (see below)!

 NOTE: Skill checks come into play in unusual or significant situations.  Characters should not have to make skill checks in completely frivolous or
 mundane situations. For example, a character wouldn’t need to make a Climbing skill check if he or she were trying to reach the top of a low hill, or even if trying to pass through mountainous foothills under the expert tutelage of a veteran mountain climber. On the other hand, if the PC were trying to reach the top of a low hill while being pursued by an Ark hunting party, or were racing across the same mountainous foothills while being pursued by the Knights of Genetic Purity, one or more Climbing skill checks would be totally appropriate.

Skill ratings should very rarely exceed 12. That way, even the most well-trained, naturally adept (related attribute = 18) character will fail a
skill roll sometimes under normal circumstances (on a roll of 19 or 20).
However, because the possibility exists for characters who can never fail a skill check by the numbers to enter the game due to a very high related
attribute score, or an expertise rating in excess of 12, a roll of 20 on any given skill check automatically fails. On the other hand, this is just a game, so a roll of 1 on any given skill check automatically succeeds.
 
Using Skills Your Character Doesn’t Know

For most skills, a character can attempt a skill he or she doesn’t have at an expertise rating equal to one-third of the skill’s related attribute, modified by an unskilled penalty of -3. A skill that has an unskilled penalty score of ø (null) or a negative expertise rating after modifications, cannot be attempted by an unskilled character.

 NOTE: The automatic skill check success that results from a roll of 1 does not apply to rolls made with an unskilled penalty, nor to any skill that cannot be attempted by an unskilled characters (those skills with an unskilled penalty score of ø).

 STARTING SKILLS
 All characters enter the game with class skills, plus a number of skills equal to their INT. This number is further adjusted as follows:
 

• +2 skills if the character is a Pure Strain Human
• +0 skills if the character is a Humanoid
• -3 skills if the character is a Mutated Animal
• -5 skills if the character is a Mutated Plant

 Players cannot pick class skills outside of his or her own class at this point, though they may acquire them later (see below). Once the player chooses his or her character’s skills, he or she receives a number of points equal to INT+3d6 to distribute among them. No character can enter the game with more than 8 points assigned to any one skill initially.

 ACQUIRING SKILLS
As an integral part of character development, skills don’t come cheap. The cost of improving a skill is equal to 1,000 XP times his or her current expertise rating in a given skill, plus 1,000 times the expertise rating the character is trying to obtain. A character cannot raise a skill level’s expertise rating by more than 1 over the course of any given play session.

For example, Jorgreff the Barbarian wants to raise his Climbing expertise rating from 4 to 5. This will cost him 9,000 XP (4 x 1,000 XP for his current expertise rating, plus 5 x 1,000 XP for his target expertise rating). Although Jorgreff has 50,000 XP to spend, he may not increase his expertise rating in Climbing above 5 during this play session; he must wait for the next game to raise it to 6, and the following session to raise it to 7, and so on, despite the fact that he has more than enough experience points to pay for such an increase right now.

Acquiring a new skill costs 3,000 XP. Acquiring a class skill from outside of a character’s own class costs 5,000 XP. Newly acquired skills always have an initial expertise rating of 1.

A character may improve an unlimited number of skills during the course of any given play session, so long as none of them are improved by more than a single point. Characters may only acquire one new skill per gaming session.

 NOTE: This rule replaces the skill advancement rules on p. 25 of the Gamma World 4th ed. Rules. In effect, characters now must choose between
 allocating experience points for level advancements and corresponding increases in hit points, mutation power scores, etc. or improving their skills (including class skills).

Let's make this a combined-list project! Send me the info, and I will add it here.