How can i use an at&t phone with tmobile service?

[JazmineR]

I have Tmobile but i want the Sony Ericsson from at&t

 

[jocoolguy]

To use T-mobile In the AT&T Sony Ericsson Phone,you need to unlock it.You can get the unlock code from the site Theunlockarena.com and unlock it easily....you need to specify the model and get the code and unlock it easily.Then use T-mobile sim in it.