What does a CUDA driver do?
Nvidia offers a CUDA driver and OpenGL driver, for use with their APIs. The application would need to be recompiled with these options for the .app to use the cuda driver. 

Here is the latest info, from a last month...
http://developer.nvidia.com/object/cuda_3_2_downloads.html

Scroll down to Mac OS X section for some good non-programmer - adv programmer info.