The Apple server are closed ! time is over ! It dose not work any more
What do you need: A jailbroken iPhone that can be activated in iTunes (that is, not officially blacklisted), a computer with the latest iTunes installed and working internet connection. You will also need to know the carrier that your iPhone is locked to.This will unlock all basebands like 4.11.08 , 4.12.01 ,1.0.13 ,1.0.14,2.0.10
Updated with new solution
To unlock your iPhone 4 on iOS 5 with Gevey SIM you MUST update your iPhone 4 to pre-jailbroken custom firmware to preserve the unlockable baseband which are compatible with Gevey SIM.
The Gevey team introduces Gevey SIM Interposer, a small chip to unlock iPhone 4 on 02.10.04,03.10.01 Baseband and iOS 4.1, 4.2.1 , 4.3, 4.3.1, 4.3.2, 4.3.3, 4.3.4, 4.3.5 . This reminds me of the good old TurboSIM days, a popular method for unlocking iPhone 2G in 2008.
The popular Gevey SIM Unlock solution for iPhone 4 has been blocked by Apple in iOS 5 beta 2. Gevey SIM works fine on iOS 5 beta 1, but MuscleNerd of the Dev-Team has confirmed that Apple has patched the exploit used by Gevey SIM to unlock iPhone 4.