One of my friends has just acquired a relative's old iPhone 3GS, and he wants to jailbreak and unlock it so he can use it on his carrier. I've jailbroken iPod touches using RedSn0w before, but I'm relatively new to the idea of basebands and the more phone-specific parts of jailbreaking. The iPhone is on a version of iOS 3 (I can't remember the specific version). As far as I know and have read, there isn't a full jailbreak for iOS 5.0.1 (which is what iTunes automatically prompts an update to), and Apple don't verify any older versions of iOS any more. What is the best way of jailbreaking and unlocking the phone from this point? Any advice will be very much appreciated. Thanks in advance!