I am getting married on November, and just finished emailing our lawyer all of the required documents. We were told you need:
1) color copy of birth certificate - my fiancee lost his also and we had to get a copy from the State of Maine (we live in NY) relatively easy, filled out a form and paid like $15. It came in the mail about 2 weeks later
2) passport - valid for at least 6 months after the wedding date
3) a document stating neither of you have been/or are currently married - we had to go to City Hall and get an "application for license to marry outisde of the US" - or something. That was the only thing that stated we weren't previously married. This was easy but a little annoying, had to go to 2 other offices to get it notarized, etc ...
Hope this helps!