While Apple’s new iOS 6 update brings a lot of new features, and significantly improves the iOS experience for most users, not everyone is thrilled with Apple’s changes. Fortunately for you, it’s still possible to downgrade back to iOS 5.1.1!
It’s also worth noting that the downgrade doesn’t always work using iTunes 10.7, and downgrading your firmware is absolutely not supported by Apple. I’ve successfully downgraded my iPhone 4S using this method, and can confirm that it worked for me.
This will also stop working once Apple stops signing the iOS 5.1.1 update, so proceed at your own risk. Neither MacTrast nor Mac|Life are responsible for any damage to your device. Check out the original link at Mac|Life for download links and full instructions.
Update: The below video from iJailbreakMovies explains the process, and may make it easier for some. The video was intended to provide instructions for downgrading iOS 6 beta, but the instructions remain the same.