OK, so I've got a pretty long story here. Hope you guys can help me out. About a month ago, I bought an iPhone 3G off of Craigslist and it came with iOS 4. I jailbroke and unlocked it using Pwnage Tool and Ultrasn0w. I was easily able to sync it to iTunes. Then, I sold the 3G and bought the 3GS to have something faster. However, that 3GS came with OS 3.1.3 and the new bootrom and I jailbroke and unlocked it before syncing it to my laptop. The owner did not give me any SIM with it and I only have my T-Mobile SIM. Afterwards, I tried syncing the 3GS to my laptop and it says to either set up a new iPhone or restore what I had on my jailbroken 3G with OS 4.0. Now, I have no idea what to do because I am afraid I will have to activate the iPhone 3GS if I try to set up a new iPhone or restore it and I don't have any ATT SIM or even a Phonebook SIM (of which I heard people are having problems with). Right now, I have the 3GS working with OS 3.1.3 but every time I put in the USB charger, all it does is charge and iTunes shows me the setup or restore page. I want to be able to upgrade to iOS 4 and sync my music, contacts, etc. I have heard that you can buy an inactive ATT 3G SIM from ATT and use that to activate the iPhone. Unfortunately, no one I know is willing to let me borrow their SIM. I desperately need help with this. Someone please reply. Thank you.