Would like to see some of the senior hacker perspectives on this. I was able to install my sim from my ipad (with a sim adapter) into my iphone. Called ATT and they activated it no problem. Phone calls in/out work on a 3g tower. Internet only works on edge if I shut off 3g, but if 3g is on I get a message: "Could not activate cellular data network. You are not subscribed to a cellular data service" I definitely have the data plan on my iphone. When talking to ATT tech when setting up the phone they said everything was set up perfectly on their end and to just let the phone sit overnight and reset the network in the morning. I did all that and no change. Anyone care to venture a guess? I'll be replacing the sim with a regular iphone one later on today, but it would be seriously nice to solve this for anyone else who would like to swap out their sims like this.