How to Unlock the iPhone 4S without any jailbreak or the crack. here is Step by Step guide
Step 1: Insert the Original Carrier AT&T SIM card.
Step 2: Dial 611 for customer service, and once it starts ringing, hang up.
Step 3: Turn on the Airplane Mode.
Step 4: Take out the AT&T SIM card and insert the T-Mobile SIM card.
Step 5: Make sure the Wi-Fi is off, and clear any remembered networks to ensure it does not auto-connect later.
Step 6: Switch off Airplane Mode and iPhone will search for network. This is followed by the Apple splash screen appearing.
Step 7: Activation Required will be displayed on the screen.
Step 8: Once you notice the device has found an EDGE network (E symbol), wait about 20 to 30 seconds and turn off the phone.
Step 9: Turn on iPhone and the same Activation Required screen will be displayed.
Step 10: Once you notice a signal bar, hit Use Cellular Connection.
Step 11: Eject your SIM card, after which you will see the activation notice for the third and final time.
Step 12: Insert your SIM card.
Step 13: Your iPhone is Unlocked!!
Step 14: Happy?
Step 15: Enjoy