CamTap Cydia Tweak removes the "slide to unlock" bar and puts the camera grabber on the center of your lock screen. To unlock your device swipe up on the Camera Grabber, to open the camera just tap on it.
Check the video review after the break.
There are no options to configure, to disable the tweak just remove the package from Cydia.
CamTap jailbreak tweak is available in Cydia under the BigBoss repo for free.