I unlocked and jailbroke my iphone 3g no problem. Then I got a Tmobile pay as you go sim card, put it in, and it worked for the first few days. Now I buy and sell iphone and jailbreak and unlock them on ebay, and I just unlocked+jailbroke another iphone 3g. I put my tmobile sim card in it to test if it worked, and it just came up as no service. (I always get service here, I restarted it, and unlocked again, still no service.) Then I put it back in my iphone 3g and it said no service. I've been moving around trying to get service and restarting my phone, nothing. Is it possible that i switched the SIM card TRAYS of the two phones and that's causing it? Seems unlikey, but why else is this doing this? Maybe I truley have no service?