Okay, so Apple just announced OpenCL (Open Computing Language) technology in upcoming OS X 10.6. This is starting to get interesting.
My prediction? OpenCL should be something along lines of CUDA or BrookGPU. Will work on various DX10-level graphics cards, and on the CPU. I think trying to target older graphics cards does not make sense - using real actual integer types is useful in general purpose computing (DX10 tech), and Apple will probably only be shipping DX10 level graphics cards in a year (at the moment only Intel cards in Macs are DX9 level; the rest is GeForce 8s and Radeon HDs). With a multithreaded CPU fallback any older machines will be taken care of anyway (and leaves the future open for Larrabees). So yeah, quite similar to BrookGPU actually.
It has “open” in the title, so maybe they will make it for other platforms as well. I doubt that they will ship implementation though; perhaps just make it royalty/patent/whatever free and publish the spec. Which is about the same level of “openness” as other technologies with “open” in their name (OpenGL, OpenAL, OpenMP, OpenCV, …) - not exactly open, but not the worst kind either.
We’ll see how it goes.