I have 4S with iOS 5.0.1 (don't remember the baseband version. I think I didn't update it). I would like to sell it before the launch of the iPhone 5. Do I have to both jailbreak and unlock the device or jailbreaking is enough to sell? If I need to do either or both, what is the best step by step way to successfully accomplish the task?. Also, I didn't ask AT&T on what happens to my contract information when I sell it.
On the other hand, is there any other way of selling my 4S for a good price to enable me to get 5?