At this moment in time. No. Only one game (last time i checked) supports them and that is Ghost Recon: Advanced Warfighter. And the physics that the card enable arent game changing. Plus if your graphics card isnt the best the game can actualy slow down because your card has to render more objects.
Admittingly, I'd love to have a go with PPU cards - but the price really makes it hard - plus the benefits aren't always apparent.
Problem is, that the current PPU cards do not add greater performance, but more visual awe (highly debatable on extent) at the same performance level. This makes it hard to sell, and market the hardware. With a slow market inception as a result, the push into PPU accelerated games is just so slow, that it just might fall over and break it's back.
One must also consider the move with dual core and quad core cpu's and the possible benefits therein. I was informed previously, that PPU uses high FP calculations, the area where current CPU's aren't strong in. But just maybe future CPU's might have a better FPU unit or bigger transistor count.
Or, Ageia can maybe work harder at promoting their product, with a better price entry point and deeper market support. The potential is there, but it's still early days. Here's hoping...
From what I heard of the new Ageia Physx card is that the physics algorithms are locked in the core. making it impossible to update it or improve upon it.
Spending ~$300 on a PPU dosent make sense when it could be software simulated or have the video card take some of the load. Like the planned physics processing for SLI.
Nvidia has just made a board with 3 full 16x pci-e slots, two of which for graphcs cards, and the third for their soon to be made and released ppu. I'd wait a while to see what they have to offer, and by then, more games will take advantage of it.
There are also other alternatives to the stand alone ppu card on the way. Be patient.