Unlock iOS 5.0.1 On iPhone 4 / iPhone 3GS Using Ultrasn0w 1.2.5

unlock the following basebands:

• 01.59.00
• 04.26.08
• 05.11.07
• 05.13.01
• 05.12.01
• 06.15.00

Step 1: Jailbreak your device using the latest release of Redsn0w or Sn0wbreeze.
Step 2: After the jailbreak procedure has finished, launch the newly installed ‘Cydia’ application that is present on your iPhone’s Springboard.
Step 3: The required repository comes as default with Cydia, but for education purposes to add a repo you will need to tap on ‘Manage’ tab, followed by ‘Sources’ and then finally select‘Add’. After completing those steps an alert will pop up with the title ‘Enter Cydia/APT URL’.
Step 4: Add the following URL into the pop up alert - http://repo666.ultrasn0w.com – then select ‘Add Source‘.
Step 5: After Cydia has finished refreshing and adding packages, tap on the above mentioned repo and install the Ultrasn0w utility. Congratulations, you are now the owner of an unlocked iPhone.