You will need a passport next year!
The rule's first phase will go into effect December 31, 2005, requiring all U.S. citizens traveling by air or sea to or from the Caribbean, as well as Central and South America, to have passports. The next phase, which will apply these rules to all air and sea travel to or from Mexico and Canada, will begin a year later.
The last phase, which will affect the most people by far, will take effect on Dec. 31, 2007, and will apply the requirement to all air, sea and land border crossings with Mexico and Canada.