ATI releases beta SDK with OpenCL CPU support
At run time, OpenCL will detect what kind of hardware you have and run your OpenCL kernels across that hardware. If you have a quad-core CPU, it will use all 4 cores, and if you have a compatible GPU graphics card it will use that. In theory OpenCL will take the place of CUDA, CTM, Brook++, OpenMP, Intel TBB, and pthreads for many common compute-intensive workloads.
Unfortunately the current beta comes with some severe limitations. At this point it supports running code only on the CPU, not the GPU. Also, double precision floating point is not yet supported. Still, this SDK is the first opportunity most developers have had to start developing and testing OpenCL applications.
The final version of ATI's SDK, with GPU support, is due out by the end of the year. NVidia should have their own OpenCL drivers out soon, and Apple's Snow Leopard will be out soon with some kind of support. Hopefully by this time next year everybody will have access to production-quality drivers so ISVs can start considering this for commercial systems.