GSM (global system mobile) should work overseas, just fine. The US is one of just a few countries that use other carriers other than GSM. Most every other country uses GSM. However, you should ask AT&T; what the fee's will be for using your phone in another country.

Highly suggest you check out your international roaming fee's. Make sure you fully understand the data plan for such travel as well. Horror stories are abundant on this very topic.

There are now two service that will unlock an iPhonen for you, for a fee. I don’t know if they’re up and running yet or not, but they should be within a couple weeks or so. I forgot the other, but here’s one:

www.iphonesimfree.com