The OpenCL Programming Book
The book is intended for those interested in the new framework known as OpenCL. While we do not assume any preexisting knowledge of parallel programming, since we introduce most of what you need to know in Chapter 1, we do however assume that the reader has a good grasp of the C language. Those who are already experts in parallel programming can start in Chapter 2 and dive straight into the new world of OpenCL.
The official reference manual for OpenCL can be found online on Khronous' website at: http://www.khronos.org/opencl/sdk/1.0/docs/man/xhtml/
Sample programs in this book can be downloaded at http://www.fixstars.com/en/books/opencl