I checked the T-mobile website for personal coverage and drove there to see if I could pick up T-mobile but it only would give me Cingular to choose manually.

T-mobile's network in the USA is far, far, far less complete than Cingular's.

T-Mobile basically covers MAJOR cities and interstate routes. SOME mid-size cities are covered by roaming agreements with a handful of other carriers. , personally, get great Cingular GSM service at my house but bare get any TMO service there. And that is in a suburban part of a very major city.

Since Virgin UK operates on the T-Mobile UK system, I'd ahve thought that Virgin UK would have had a roaming deal with T-Mobile USA, like Orange UK does. Humph!

I put my Virgin sim in a quad band phone that I know picked up a T-mobile signal (ie had a Tmobile sim) and tried to manually change networks and it still would only come up Cingular. It might be that since I have Cingular coverage, they don't allow you to manually change unless their coverage isn't available.