Gee, maybe I should read the Snow Leopard specs on Apple's own website before speculating on what works and what doesn't. According to Apple, Open CL compatibility works on the following GPUs:
Geforce 8600M GT, GeForce 8800 GT, GeForce 8800 GTS, Geforce 9400M, GeForce 9600M GT, GeForce GT 120, GeForce GT 130.
Radeon 4850, Radeon 4870
That would mean that my wife's Macbook Pro Santa Rosa is capable of OpenCL acceleration, but right now I don't have any way to test this. But for H.264 acceleration, only one GPU works:
That means that although my Mac Mini 2009 can't do OpenCL, it can to H.264 in hardware (and curious that none of the fancier chips in the iMacs, MacBook Pros or Mac Pros can't). Well, I'll test my Mac Mini later today and see what it can do.