Step 1: Install iOS 5.0 or 5.0.1 on your iPhone 4 using iTunes.
Step 2: Download the recommended software on this unlock website with the money-back guarantee.
Step 3: Launch recommended iPhone 4 unlock solution, and connect your iPhone to your computer via USB cable.
Step 4: Click on “Jailbreak Now” button to jailbreak your iPhone 4 device.
Step 5: Ignore any prompt that may appear on your device.
Step 6: Wait for Absinthe to complete building of jailbreak data. Once it is done, you will be notified.
Step 7: Now, look for Jailbreak or Absinthe icon on your device.
Step 8: Tap the icon to install Cydia. If you get database connection error message, quit the program and keep trying.
Step 9: Once you are able to complete Absinthe installer on your device, Cydia icon will be found on your spring board.
Step 10: Tap on Cydia and install it completely to unlock your iPhone.