does one need passport or birth certificate to enter the country????????????

You need a passport.

Passport must be valid until a date that is at least 6 months after the date of your return trip ticket.
Passport must be in good condition - two weeks ago I saw Continental Airlines refuse to allow a man to board the flight to Belize because his passport had water stains on it. The poor guy was there with fishing rod, suitcase and three fishing buddies. He claimed that he had been all over the world with this damaged passport - airline personnel were helpful, but firm. He was assisted in finding immigration so that he could make an emergency application for a new passport - they assured him he could "probably" travel the next day. This screening occured at the gate, not at check-in.
DO be prepared with all the right papers before your trip. You do not want this to be your vacation story!

Hurry up and get the application working... it took me about 3-4 weeks to get mine in the mail.

My wife works at the post office and does passports My recomendation if you are within 8 weeks of your travel date go ahead and pay for the expidited service beleave me it will be back to you in 10 to 14 buisness days
J D

got my passport in 3 days. now, i live in Philadelphia, where one of the regional offices is, so i could physically go there and get it done. cost about $200, but i had it in 3 days

you can get it same day or next day service in 5 places in the states, google it.

yep... remember that... I was going the cheap route... and it still cost over $100. I knew I wasn't going anywhere soon, so it was cool to wait... but if you plan to go on a trip soon, the expidited service is the best way to go. Good luck!

This link may help with your search...
http://travel.state.gov/passport/passport_1738.html

but they last for 10 years so you only have to mess with it once in 10 years