How to unlock iphone 4 to tmobile?

I want to unlock my iphone 4 to tmobile help i never done this before its on 5.1.1

A gevey sim, or att.
att will unlock it if your a current coustomer and the iphone is off a 2 year contract.
there's no other way.

You have to jailbreak it with redsnow.download link for mac: https://sites.google.com/a/iphone-dev.com/files/home/redsn0w_mac_0.9.10b8b.zip?attredirects=0&d=1

download link for windows: https://sites.google.com/a/iphone-dev.com/files/home/redsn0w_win_0.9.10b8b.zip?attredirects=0&d=1

And then go to this site: http://www.redsn0w.us/2012/05/jailbreak-ios-511-untethered-on-windows.html to find the rest of the instructions on jailbreaking and then you can unlock with this site: http://www.redsn0w.us/2012/05/ultrasnow-fixer-updated-to-unlock.html

Call att to unlock it.

You can unlock an iPhone 4 safer and easier through remote unlocking method. It is also an affordable method too. You can get the remote unlocking for an iPhone from http://www.unlocking4u.com/apple-iphone-4/rs6wp9/ This site is a legit source to rely on accurate unlocking solutions. All the best mate.
Here are the steps for unlocking an iPhone4,
1. Wait for us to send you an email saying your phone has been activated or remotely unlocked.
2. Install the latest version of iTunes.
3. Make sure your Apple iPhone 4 phone software is updated to the latest version using the iTunes software.
4. Connect your Apple iPhone 4 to iTunes with a NOT ACCEPTED SIM card.
5. Wait until iTunes detects your Apple iPhone 4.
6. Disconnect your Apple iPhone 4 and reconnect it after 10 seconds.
7. Your Apple iPhone 4 is now unlocked.