Redire is a new modification for which you have the tethered jailbreak IOS 5.1 on your iPhone 4 or earlier, and allowed to leave the camera button on the lock screen as it was in iOS 5.0.1
With the slider you can transform redire camera fixed the lock screen of IOS 5.1 for a button that appears when you press the Home button twice as many have now in our iPhones with iPhone OS 5.0.1. Installed and ready, do not configure anything.
You can download it for free on Cydia, you'll find BigBoss repo. You need to have jailbroken your device.