Get your Passport...

New Passport Requirements for Travelers Between the United States and the Western Hemisphere.
Travelers to and from the Caribbean, Bermuda, Panama, Mexico and Canada will be required to have a passport or other secure, accepted document to enter or re-enter the United States. This is a change from prior travel requirements and will affect all United States citizens entering the United States from countries within the Western Hemisphere who do not currently possess valid passports. This new requirement will also affect certain foreign nationals who currently are not required to present a passport to travel to the United States. Most Canadian citizens, citizens of the British Overseas Territory of Bermuda, and to a lesser degree, Mexican citizens will be affected by the implementation of this requirement.
The travel initiative requirements will be rolled out in phases, providing as much advance notice as possible to the affected public to enable them to meet the terms of the new guidelines. The proposed implementation timeline is as follows:
December 31, 2005 – Passport or other accepted document required for all travel (air/sea) to or from the Caribbean, Bermuda, Central and South America.
December 31, 2006 – Passport or other accepted document required for all air and sea travel to or from Mexico and Canada.
December 31, 2007 – Passport or other accepted document required for all air, sea and land border crossings.
From Travel.state.gov ( http://travel.state.gov/travel/cbpmc/cbpmc_2223.html) US Department of State