Okay here's something to keep in mind if you're planning on taking your iPhone overseas. Apparently, a boing boing reader decided to use his iPhone in roaming mode in the UK and Ireland, but didn't bother to figure out how the $0.005/KB rate would translate into real-world usage. Well two weeks of "sporadic AT&T EDGE network usage off and on mixed with wifi when available" came to $3000!
After the story got legs on the 'net, AT&T apparently decided to waive the charges. It seems that AT&T offers an unlimited international data plan for Blackberry users, but not one for the iPhone. Nonetheless, there's a lesson here for international travelers. Keep to wifi when overseas if you don't want to get stuck with massive roaming charges.