Hey. What are the differences between the iPhone on AT&T and the iPhone on TMobile or another carrier that you can unlock it for in terms of price and features. Also, can you unlock the iPhone 3G on 2.0 or 3.0? Sorry I haven't been here in a while and I need an update. I'm thinking about buying an iPhone but I'm on another carrier right now and for AT&T the iPhone for 2 years comes out to about $2200 I have heard with everything so there could be a better option. Thanks.