Apple ipod

How to activate the iPhone 3G prepaid SIM card?

Hi, I have a 3G iPhone and I have 3.1 days accidental. Now my phone is locked and has a slider for emergency calls only. I have a SIM card from AT & T prepaid phone a go-bought. I put that on my phone and connected to iTunes (since it has the image recovery after emergency calls only cursor), but itunes tells me I have to put a valid SIM card inch "SIM card not seem to be compatible. only compatible with SIM cards can be used … I'm confused and I do not know what to do. Please help me. I feel very sad that this happens, as I have it just as well. I know it was stupid of me to improve, but please let me know a solution. Thanks for your time.

AT & T is not compatible with the iPhone as a prepaid phone, then handed the SIM card is not working. You have to get AT & T contract.

3rd Generation Apple iPhone 3G S Universal Sim Free Unlock Mail in Service – B