I've traveled to Europe with my iPhone before, and despite activating an international data plan I ended up spending a bit more than I wanted to (by about $100). But Raven Zachary came back home to a $800+ bill, and there are many tales of others having even worse experiences.

Raven wrote a blog article offering some tips to keep your costs down, all of which are good. So, if you are traveling out of the USA with your AT&T iPhone (and yes, that DOES include to Canada or Mexico, so do your homework), check out what he wrote.

As of today, there is no "unlimited" international data plan available. It can get very expensive to deal with email attachments and use the maps program, or even just to check email the same way you do back home (meaning automatically every n minutes). With the 3G network coming on the new iPhone and the associated roaming costs for high-speed access projected to be higher, this all becomes even more important.

Until AT&T makes it a little easier to be their customers, and simplifies things for those of use paying them big bucks for service, you'll need to order specific international services and configure your iPhone in certain ways to make sure you don't get nailed and you'll have to search the 'net to find sources to read about the problems and related solutions. I feel sorry for people who get completely blindsided (and there are a lot of those people out there). So much for seamless, don't-have-to-think-about-it use, eh?