So would someone like to explain the differences between pre-pay and post-pay with AT&T? I don't really get the difference other than the time when your bill arrives. In addition, what is the policy on overages? Do you have to manually decide to continue using data, or will the companies just automatically charge you the additional fee once you've hit that line? I remember hearing that AT&T gives you a new 30 days when you go over, so it's just like resetting your plan. But do you get any notification that it has happened? Can you check your usage? And what if you want to change plans when you go over, is that possible? Sorry for all the questions, but I want to go 3G with the new iPad, so I need my information straight before hand.