not sure if this can be done but i have a 8100 pearl on tmobile and was looking to pick up a curve someone has but its a att phone is there any way i can completly remove att's operating system and install tmobiles?
You haven't checked good enough. If you search the forums for unlocking the phone or even do a google search then you will be able to use ATT service on a TMO phone and vice versa. So first you have to unlock the phone and then you can do what you want.