So if any of you have been following my immense amount of threads lately dealing with my frustration in not being able to get a prepaid sim to work in my iPhone 3G with 3.0, I have figured out why it wasn't working-even after unlocking the phone. Certain prepaid GoPhones from AT&T lock the sim to the goPhone. Supposedly even if you can get a customer service rep to change the IMEI, it still won't work. After reading through my pamphlets with the goPhone I did find the information.. "For new GoPhone customers, once the device and SIM are activated SIM cannot be used with any other device for a set period of time..." I believe that is 180 days from reading threads about it in another forum. Anyone know of another pay as you go sim that will definitely work? I need to get one asap. Thanks!