I am almost finished jail breaking my iphone 3gs and I have gone through this process repeatedly! Once I get SO close to finishing, it just freezes. It starts rotating like it's loading. But then it just freezes. It's been like this an hour now. I could go back and repeat the process, but I have repeated it like 20 times. I have it almost perfect so I don't want to retry. I will if I have to, though.