I'm preparing to port my land line to a mobile phone. I have the T-mobile sim card. Do I have to insert it into a T-mobile phone or can I use my leftover AT&T phone?
If I not mistaken, your AT&T "leftover Cell Phone" would have to be unlocked in order to accept the T-Mobile SIM Card. If it is not unlocked from the AT&T provider, is it possible that they will give you the unlocked code if you requested it? Do you still have Mobile Service with AT&T? Does any of your Friend or Family have AT&T Service?
I just did this & had to get my old AT&T phone unlocked.
Call AT&T support & tell them you want to unlock your phone. They'll ask for the phone IMEI number & will give you an unlock code. Then insert the T-Mobile SIM, turn it on & enter the unlock code.
Check out this post: http://www.obitalk.com/forum/index.php?topic=1051.0