If you want to find information concerning birth certificates, it may be obtained at the Vital Statistics Office. The address follows:
011-684-633-1405 (voice)
011-684-633-7910 (fax)
If you want a copy of your birth certificate you need to write the Vital Statistics Office a request letter with the following enclosed.
That should do it.
Note: Since this is a US Territory regular US postal rates apply. If you are in a hurry send the letter via "PRIORITY MAIL." DO NOT send it via EXPRESS MAIL as there are only two flights in here a week; Monday and Friday nights, and thus it will be no faster than PRIORITY.