You won't get charged for extra data use. You have unlimited for a reason, use it however you want. Trust me, ATT doesnt care. They dont look into your account and look over your data use thats just stupid. Back in early january of 08, I hacked my phone with SwirlyMMS to get MMS on my iphone and ON MY BILL it said under messages: MMS Messages and it listed off each one. Now let me ask you a question. If ATT actually looked into accounts, do you think it would be odd for them to see an iphone sending MMS messages? I mean it was clearly half a year before 3.0 came out so no iphone had MMS. So bottom line, ATT doesnt care, they have 10's of millions of people on their system to be "looking over" they're not going to see your "excessive" data use.