How to unlock an iphone for tmobile?

I have an iphone 3g, version 5.1.1, and have gone through the process of jailbreaking the phone, using ultrasnow, watching numerous videos, and going into airplane mode and rebooting. For some reason it still does not read my sim car, can someone help?

Tmobile sells iphones

Unlocking is different from Jailbreaking. Once you have jailbroken your iPhone you need to unlock it separately. You can unlock an iPhone through remote unlocking method. This method of unlocking is safe, simple and affordable. You can get the remote unlocking for an iPhone from http://www.Classicunlocking.com/ This site is a trustworthy source providing accurate unlocking solutions at affordable cost with easy step by step unlocking instruction guide.

Ultrasn0w works on selected basebands

04.26.08
05.11.07
05.12.01
05.13.04
06.15.00

Make sure you're on a supported baseband. If not, there's a way to get to a supported baseband.

First you will need to upgrade to 06.15.00 using an older version of redsn0w… Once you're there, your SIM should start working however your GPS might not work.

Once the SIM starts working, you should be able to downgrade again!

Use ultrasnow.