I bought an iPhone 3g 8gb from someone and when I insert an AT&T sim it does not read it. However when I remove the sim tray the "No Sim installed" message pops up, so I assume it knows a sim card is inserted. This phone is jailbroken, V 2.2.1 and 02.30.03 baseband. I'm doing a "restore" with iTunes but not sure if it'll work. I looked up the serial number and it says: "Our records indicate that your product is covered under Apple's Limited Warranty which is estimated to expire on September 05, 2009. Your product is eligible for complimentary phone support which is estimated to expire on September 06, 2010." I was just thinking of taking it to Apple after doing the restore but I have no receipt, will they give me a new one? Appreciate any input.