Keep in mind that if you don't have 3g and unlimited data then this won't work for you.
Transferring that amount of data over the ATT Edge network just won't cut because it's slower than dialup and if it is on 3g then you're going to move so much data then it will rack up your usage quickly. New ATT users can not get unlimited data, they have to get a data package. Past users are grandfathered in.