Remember the differences between voice, data, and international roaming. THis gives you access to the different capabilities and it is easy for TMO to get the setting wrong. Make sure they are all activated voice- intl and data-international.

Then the amount you pay depends on the plan. Either you pay roaming on the per mb system, or you give them $20 per month and you get all the email you want, but still pay for general internet. This is different than Cingular, where the international plan includes unlimited data (including internet surfing and other data traffic)