Let me give you the whole story... Okay here we go: I bought an iPhone the first day they came out. I then waited months and months for an unlock. I paid the $50 dollars for IPSF (iPhone Sim Free) and unlocked my phone for T-Mobile with that. I have left my phone the way it was since then using T-Mobile and software version 1.0.2 being scared to mess anything up if I updated my software version. My service agreement with T-Mobile ended in January so I switched to AT&T. I had my number transferred to my new "free" phone with AT&T at which point my iPhone with my T-Mobile card still in it said "No Service". I tried to put my new 3G simcard from my new phone into the iPhone but it says "Incorrect Sim Connect to iTunes". I connected to iTunes and tried to activate it like a new iPhone and went through all the steps but on the last step when it was activating it iTunes said it couldn't do it and to try at a later time. Weird thing is I put my friends Cingular card in my iPhone before and it worked just fine but now it says "Incorrect Sim". Anyhow now I just figure restore everything back to factory and sign up with AT&T. Can I do that? If so how? Can up unlock it with anything else? I was also thinking about upgrading to the new 16gb model..... can I with my phone if I restore it back to factory? Please any feedback would be very helpful.