...from: http://www.nytimes.com/2007/09/10/technology/10iphone.html?th&emc=th
[...]
Other iPhone users have felt the sting of high roaming charges with their iPhone, too. Some, like Mr. Dingman, are unaware that they need to disable the e-mail feature; others are billed erroneously; still others misunderstand the explanation of charges they are given by AT&T customer service representatives.
The iPhone is no different from any other phone, said Todd Smith, an AT&T spokesman, with the exception of the BlackBerry, whose users can opt for a flat monthly rate when traveling. Any AT&T customer planning to travel outside the United States should contact AT&T to inquire about roaming plans, he said.
Dave Stolte did that before taking his iPhone with him on a two-week trip to Ireland and England in July. He signed up for a roaming plan, but he said the customer service representative’s explanation of the charges was unclear. His bill was $3,000.
[...]
In July, Aaron Oxley took his iPhone with him to London, Dubai and Bangkok. Mr. Oxley said in an e-mail message that he was aware that there would be international roaming data charges, so he always made sure he was in an area with free Wi-Fi when he used his iPhone to access the Internet. But when Mr. Oxley’s AT&T bill arrived, the data charges [erroneously] totaled $300.
When Mr. Oxley called AT&T, he was told that even though he was using Wi-Fi, there was still a data transfer charge.
According to Mr. Smith, the AT&T [spokesman], iPhone owners are not charged for Wi-Fi connections. Mr. Oxley eventually received a full refund for the $300 roaming data charge.
Mr. Dingman said it didn’t occur to him to disable the e-mail feature. AT&T eventually reversed the charges, but only after Mr. Dingman signed up for a $24.99-a-month global data plan.
AT&T is not automatically crediting customers for such charges. Mr. Smith said that each complaint is being evaluated case by case.