Can tmobile unlock my at&t iphone 4?

I don't care if you have to pay anything

Added (1). Or can at&t unlock it

Its 25 bucks

No tmobile will not unlock your att iphone.
most ppl can unlock it for $20

T-Mobile won't. If your contract is up with AT&T, you can get your iPhone unlocked from them.

No, you would be best to go to a provider that can do it in hours the same day. I got mine done at www.iphoneunlockedcheap.com in a few hours. It is worth it

Yes they will unlock it no matter what for a fee around $10

If your iPhone 4 is locked to AT&T means, you need to get unlocking service from them or from any of the online vendors like http://www.unlocking4u.com/apple-iphone-4/rs6wp9/ ( who provides Remote unlocking service in online ) to unlock it.

Note: You can get unlocking service from the locked network only not from other networks. Once, you unlock your iPhone, you can use it with any other GSM sim cards.