ClearCam takes 6 photos in 2.5 seconds, fuses them together using an algorithm called super resolution, and creates a sharper, 4 megapixel photo with less noise. There is also a QuickShot mode that takes 4 photos in under 2 seconds and saves the sharpest to the camera roll.
The capture and enhance steps have been separated so you can keep snapping photos and enhance them later. It typically takes 30-40 seconds for a good enhancement.
We spent a lot of time optimizing our code to make it run fast enough on the iPhone. A lot of our effort went into being able to align photos precisely with sub-pixel accuracy (required for super resolution), and to also do it fast.
You can install ClearCam from the BigBoss Cydia Repository.