If you are just starting to work out or you have been out of training for awhile, it can be very tough. The first two weeks are always the hardest. You get sore after the first workout and can't even move after the leg workouts. You can't do a whole lot to prevent that except start in light. The only advice I can give is after a month or so you will be happy you stuck with it. People will start to comment on how huge you look or how much weight you lost. The best reward is when the sleeves of your favorite shirt don't fit anymore and people start to ask you advise on how they should workout. Stick with it and I promise it is worth it.

To start out with you will probably only want to work a muscle once a 
week.  I find that when starting, it is hard to do the same muscle 
twice in one week.  After a good first workout you will find that 
even four days later you still hurt.  For this reason, I advise a 
workout like this.  Note if this one doesn't look good to you switch 
it. I only recommend something like this.

Monday:     Chest and abs
Tuesday:    Back and Biceps
Wednesday:  Off or Cardio
Thursday:   Shoulders and triceps
Friday:     Legs
Saturday:   Off or Cardio
Sunday:     Off

If you try something like this and feel that there is too much rest,
don't take off on Saturday.  Start the cycle over.  After about three
weeks using this routine, I would recommend switching to another one 
that is a little more rigorous.  Check out my workout section for 
some ideas.  

Always remember that what you eat is a direct factor as to how your 
body looks.  You can workout all you want and eat nothing but fat and 
I promise you, you will not be happy with your results.  Eating is 
an important factor.  If you eat healthy you do your body lots of 
good.  Good Luck!