For this unlock to work, you have to already have a jailbroken phone. So you have to first have your iPhone jailbreak for iOS 5 completed before starting the unlock process.
The repository we are using is : repo.bingner.com and you can add that in the Cydia menu under add new package. You might be able to use this same process on a tethered jailbreak of the iPhone 4s or 3gs but we cannot confirm this for sure. It will definitely work though on an untethered jailbreak on iPhone 3gs or iphone 4 running 04.11.08/04.12.01 baseband.
You then need to start the app that was downloaded from the repository and deactivate the sim. Followed by inputting the new sim.
For more details on how to complete this unlock, watch the video below. Thanks as always and we appreciate any comments.