That's good advice, before I found this thread I already had AT&T corporate put a note on my account for a free SIM card, but I don't think it's the SIM. I can use my sim in a different (3G) phone and connect just fine. If I put my sim in an old EDGE motorola I have as an emergency phone, it doesn't work though. So maybe it's some sort of problem specific to EDGE on AT&T's net.