Can tmobile unlock my at&t iphone 4s?

I don't want at&t to do it.
if yes how much would they charge?

Added (1). Originally i got it from at&t but i simply don't like at&t so i want to get it unlocked to tmobile BUT i don't want at&t to unlock it for me i want tmobile to do it for me

Tmobile can, but only if they're your carrier. So basically, you're paying for a switch. Which would also require a termination fee of 175$.In the end, it would cost you 200$ to get tmobile to unlock your phone.