I have a 4s right now and my Nexus is coming in next week. I heard even though the iPhone takes a micro SIM, that you can fit it in the Nexus and position it so that it works. So I had no intention on going and getting a new SIM or purchasing an adapter. I talked to a manager I know at AT&T and he said I would have to let AT&T change my plan for a different phone (still keep my grandfathered unlimited). I'm reading otherwise though from other users. Does anyone have insight on this?