The new U.S Western Hemisphere Travel Initative made it required for all travelers entering or re-entering the states on a plane to have a passport. If you getting there by land or sea you must have 2 forms of identification such aas your birth certificate or naturalization certificate and a drivers license.
Probably in 2008 you will need a passport, but they are working on a PASS card (Passport card) that is the same size as your driver's license, but costs less than a passport. But that will only be good for going to Canada, Mexico, the Caribbean and Bermuda.






