I bought an iPhone 3gs 16gb black in march and am hooked on wanting to pre order the iPhone 4g despite the crazy no contract fee. What is my best shot at getting money out of my 3gs? Is ebay the best option? My phone is in superb condition how much should i try to get for it? Also, when/if i sell my 3gs, will the iPhone 4 come with a new and different sim card? Thanks for your help, I am new to att and the iphone world.