Shinryu and me, accidentally realized of a way of using my goPhone AT&T account that I use in my unlocked iPhone 1.1.4 Firmware and his brand new AT&T $70 contract with AT&T. We just swapped the SIM cards and you can actually use everything the iPhone has with the prepaid capabilities, and there is no hacking or unlocking involved. You can watch a YouTube video we prepared in the following link

[ame=]YouTube - Using GoPhone with the new version of iPhone 3G no hacking[/ame]