RFID chips will become part of your passport starting next year. Another application that makes more sense right inside the body.

“The Department [of State] intends to begin the electronic passport program in December 2005. By October 2006, all U.S. passports, with the exception of a small number of emergency passports issued by U.S. embassies or consulates, will be electronic passports. The ICAO specification for use of contactless chip technology requires a minimum capacity of 32 kilobytes (KB). The U.S. has decided to use a 64KB chip to permit adequate storage room in case additional data, or biometric indicators such as fingerprints or iris scans, are included in the future.”

http://edocket.access.gpo.gov/2005/05-21284.htm

It’s probably not as a well known that biometric information (fingerprints, retinal scans) are part of current ports of entry procedures.

“The U.S. Department of Homeland Security (DHS) announced today the scheduled ?expansion of the US VISIT program’s biometric entry procedures to additional ?land border ports of entry (POE)…US-VISIT entry procedures have been operational in the secondary inspection areas of the 50 busiest land border ports of entry since December 29, 2004, ?and are also in place at 115 airports and 15 seaports.”

http://www.unitedstatesvisas.gov/visanews/index.html