I tried Cingular pre-paid on a recent trip to the US. It was cheap at only $10 for I think 30 minutes or so. However the service was pretty poor. A couple of times people called and got a not in service message. I tried calling the number myself when I had full bars on the phone and got the not in service message. So they obviously use a different authorization and accounting system than the monthly subscribers use. Also, I could not setup a PIN for adding minutes. I don't know if T-Mobile pre-paid is any better in the US?