So I jailbroke my iphone 3g using pwnage successfully...I inserted my active sim card that I use on my other phone, not an iphone, and it comes up with no service after a few minutes...I have an ATT account so didn't bother unlocking it...

Does anyone have any ideas why its not functioning?

The iphone iOS is 3.1 if it matters and used the correct version of pwnage to jailbreak...