If you get a Cingular contract now, you will get a Cingular number. It would
really be up to your Cingular service office when your T-Mobile account
expires. What you can do is forward all your calls from your T-Mobile phone
(hopefully it won't effect your minutes), then when your contract expires,
you can ask the Cingular guies if they will be willing to change your
Cingular number. Then tell them about T-Mobile and see if they will do it.

That is my suggestion.

Fred