i kno this will sound nooby but what the hell is Cuda anyways?i hear ppl talking about it all the time, ecspecially in relation to Physx tech,and i dont have any idea what it is or what its for, can someone please fill me in im in the dark completley, :ph34r:
I suggest that googling might have helped a little …
Recent graphic card are programmable so that you can just program them as a simple processor (or more precisely a bunch of processors). CUDA is a programmaing model that allows you to write C-like code that is compiled to run directly on the card, in addition to some facilities such as launching code from the host or moving data around. However,  should provide an actual answer all your questions.
On the other hand, i would say that it has just nothing to do with Physx, except that Physx is just another example of the trend that consists in the use of hardware accelerators (like GPU for GPGPU then).
Somewhat, although the stream processors are not like normal CPU cores, so you have to design your programs a little differently. But yes, the idea of GPGPU (of which CUDA is one example) is to use that fancy silicon in your graphics card for something besides rendering 3D scenery, like molecular dynamics, running financial models, computer vision, radiation dosage calculations, frequency analysis of data, encoding video, finding lost passwords, etc, etc… :)