I have an iPhone 3GS that I need to sell (probably on eBay) and want to be sure I do everything right before I list it. It was deactivated (no service) at the AT&T store when they activated the replacement. I reset/erased all content. When it is turned on now it shows the Sync with iTunes screen, pressing the info button on that screen displays the EMEI and Serial number. The SIM card that came with it is still inside. Is this the correct way to prepare one for sale? What does the person buying it have to do to activate it? Take it to AT&T or can they do it through iTunes at home? Maybe even just swap SIM cards if they currently have an iPhone? I see a lit of used iPhone 3GS's going for crazy money on eBay, more than the "early upgrade" pricing. Why are they going for so much? Not that I would be complaining! Thanks for your help.