I am not very happy with Sprint currently. I have the Nexus-S 4G, and it is a great phone, had the EVO 4G before that, just that Sprint service is horrible indoors, and down load speeds on 3G are like 200k/sec and 4G is a HUGE battery killer, and be lucky to get 2mb/sec. And then being a CDMA radio you can't do data and voice at the same time, and for business having both comes in handy sometimes. I am thinking of going back to ATT possibly, and back to the iPhone, would get the i5 next month, but I also like to tinker and develop with Android for fun, and might also get the ATT Galaxy S2. My question is, does ATT still use SIM cards, and if so can I just go back and forth between the iPhone5 and Galaxy S2 on ATT with the same SIM card, just take it out and pop in either phone I want to use that day ? Or does it not work like that ?