Many developed countries are participants in the Visa Waiver Program (VWP). Citizens of VWP countries may travel to the U.S. as business visitors or tourists for up to 90 days without first getting a U.S. visitor visa at a U.S. embassy abroad. Presently, VWP visitors are able to travel to the U.S. with no prior authorization. They simply show up at the airport and board the airplane with their passport. That will change on January 12, 2009.
Starting January 12, 2009, VWP visitors must be registered with the new Electronic System for Travel Authorization (ESTA) operated by U.S. Customs and Border Protection. In advance of travel, VWP visitors must complete an ESTA registration online and receive a travel authorization before they can board an airplane to the U.S. It is recommended that travelers complete ESTA registration as far in advance as possible, but no less than 72 hours before travel. The ESTA registration Web site provides additional information under the Help link. Visit the site here.