Step-by-step tutorial: How to Unlock Your iPhone 4S, iPhone 4, iPhone 3GS Using SAM v0.1.16 [iOS 5.0, 5.0.1, 5.1]

UPDATE: Apple is blocking SAM unlock

These are instructions on how to unlock your iPhone using updated SAM v0.1.16. This method will work with the iPhone 4S, iPhone 4 and iPhone 3GS on iOS 5.x. All modems are supported.

Step One
Jailbreak your iPhone. You can find instructions on how to do that using the Jailbreak Tutorials.

Step Two
Tap to launch Cydia from your SpringBoard.

Step Three
Press to select Manage from the tabs at the bottom of the screen.

Step Four
Press the large Sources button.

Step Five
Press the Edit button at the top right of the screen.

Step Six
Press the Add button that appears at the top left of the screen.

Step Seven
Enter http://repo.bingner.com and press the Add Source button.

Step Eight
Press the large Return to Cydia button.

Step Nine
Press to select Bingner from the list of Sources.

Step Ten
Choose SAM from the list of packages.

Step Eleven
Press the Install button at the top right of the screen.

Step Twelve
Press the Confirm button to begin installation.

Step Thirteen
Once installation has completed press the large Restart SpringBoard button.

Step Fourteen
Insert your new SIM card and tap to select SAMPrefs from your SpringBoard.

Step Fifteen

Make sure your Method is set to Auto Detect and tap Utilities.

Note: If Auto-Detect doesn't work you can change Method to By Country and Carrier and select the phone's ORIGINAL carrier manually.

Tap Utilities

Step Sixteen
Press the Attempt Activation button. If you don't see Attempt Activation then select De-Activate iPhone and the Attempt Activation button should appear.

Step Seventeen
A popup will appear letting you know that "this may take a while".

Step Eighteen
Eventually your iPhone will respring and after searching for a bit your new network will be detected!

Step Nineteen
You should now backup your iPhone unlock ticket in case this method is ever blocked.

IMPORTANT:
If push notifications stop after this process, you can restore then with the Clear Push utility in SAM, followed by connecting to iTunes.

Your phone will work normally with your SIM card and that SIM card ONLY since we have tricked iTunes to think that ICCID is one of the intended carrier's. The phone can be rebooted and connected to iTunes freely without losing the "unlock", at least for now.

A big thanks to Loktar_Sun and Laforet for their contributions!

via iClarified