Apple introduced an easier way to access the Camera app with a new slider button in iOS 5.1. Simply swiping up on the home screen button reveals the Camera app.But if you don't like the new slider button to access the Camera app, then a new jailbreak tweak developed by Ron Melkhoir allows you to revert back to the original camera button. Redire is a app available for free in Cydia allows you to put back the original camera button, just like iOS 5.0.1.
How to install:
Launch Cydia > Search > Redire > Install > Reboot iOS Device