I was perusing http://www.khronos.org/ web site and only found headers for OpenCL (not OpenGL which I don\'t care about). How can I obtain OpenCL SDK?
NVIDIA is offering beta access to their OpenCL SDK. You can gain access by becoming a registered GPU computing developer. More information can be found on their forums.
It appears that ATI may be starting a limited beta of their OpenCL SDK. This website gives information about how to sign up for access to the Stream 2.0 beta, which likely includes OpenCL.