GPUImage is an open source iOS framework that lets developers create apps capable of applying GPU-accelerated filters and other effects to images, live camera video, and movies.
In comparison to Core Image (part of iOS 5.0), GPUImage allows you to write your own custom filters, supports deployment to iOS 4.0, and has a slightly simpler interface.
However, it currently lacks some of the more advanced features of Core Image, such as facial detection.
Detailed instructions on how to use the GPUImage iOS frameork within your own projects are available HERE.
· Apple Xcode