Lots of people here have Iphones, I'm not one of them, but I saw this article and thought it might be of help:
Preparing Your Iphone for International Travel
Posted by
Jonesboro, Arkansas, USA
606 posts
Excellent article. It hits all the things I did in my recent Italy trip and it really kept my bills down. Kent may want to add this article to the FAQ list he maintains, since the question comes up often. I'd add Steve's unlocked phone/SIM option too, since it's probably the best way to go, but not everybody will want to do it that way.