I am thinking of selling my original iPhone since I have a 3GS now. My original JUST got replaced from Apple, so it is new and has a 90 day warranty. Furthermore, as you know, the original iPhone had a cheaper data plan, so I feel I could get more buyers that way. Does anyone know if AT&T would require my iPhone buyer to sign a new contract, or could that be another selling point? Finally, would I include my old SIM card or does AT&T give people their own when they sign up? Thanks in advance! Also, if anyone has any idea how much I should expect, that would be great!