Great news for iPhone4S users who wish to use their iPhone on unofficial providers such as T-mobile. Today twitter user @xoicos announced a method that lets you unlock your 4S without the need for a jailbreak! This will let you use SIM cards from unofficial carriers such as T-Mobile.

Please be advised that although iBrandon tested and confirmed this method, you are doing this at your own risk. So far iBrandon has discovered a few restrictions with this method, please let us know if you find anything else.

So far, it appears that you cannot use wifi while you are unlocked with this method. Also, you will have to repeat these steps EVERY time your phone reboots in order to unlock again. This is a glitch so it is possible that Apple will be able to patch it. If you have anything to add to this post, or if you have tried it and discovered new limitations, please don't hesitate to post in the comments section!

Step 1. Insert your AT&T SIM card. Dial 611 for customer service, and once it starts ringing, hang up.

 Step 2. Turn on your iPhone’s Airplane mode, take out the AT&T SIM card, and replace it with a T-Mobile SIM.

 Step 3. Make sure Wi-Fi is off, and clear any remembered networks to ensure it doesn’t auto-connect later.

 Step 4. Turn off Airplane mode. The handset will search for a network, and the Activation Required screen will popup.

 Step 5. Once you notice the device has found an EDGE network (E symbol), wait about 30 seconds and turn off the phone.

 Step 6. Power the handset back on, and you should see the same Activation Required screen.

 Step 7. Once you notice you have 1 bar of signal, tap on the Use Cellular Connection option. Then eject the SIM card.

 Step 8. The Activation Required screen should pop up again. Re-insert the T-Mobile SIM card, and you should be unlocked.