I'm thinking about buying a first generation iphone. I use a razr with at&t and would like to know if all I have to do is put my sim card in the iphone. The only place I would use the iphone for internet would be with wifi. There is no 3g coverage in my area and I don't reallly care to pay the $30 a month for just the edge. If I did this would there be any way at&t would know?