You'll be able to download PhysX.

As you may be aware, NVIDIA purchased the company Ageia earlier this month. Ageia was the company that developed the 'PhysX' property, which they sold as a PPU (physics processing unit) expansion card. The card never made a big impact on gamers -- many felt that a dedicated PhysX card wasn't necessary, and special PhysX support didn't make into that many games.

But PhysX-capable games might become much more common in the future, as NVIDIA CEO Jen-Hsun Huang revealed that the PhysX support will be coming to Geforce 8xxx cards. The PhysX engine is going to adapted to run under CUDA, which is the programming interface that uses the parellel processing power of the 8xxxx series GPU's to run general-purpose programs. Presumably, this reworking of PhysX will make it's way into future Forceware drivers.

When exactly this will happen has not been pinned down, but it shouldn't take all that long, considering that NVIDIA retained many of the employees from the absorbed Ageia company.

Some would argue that having PhysX optimizations does not really lead to improved gameplay experiences, as current generations' of video cards have enormous amounts of processing power available, and only a small amount of that powered is sufficient for physics calculations. However, it is conceivable that with NVIDIA's weight they could push many more game developers to make PhysX-friendly games that take greater advantage of the potential of PhysX, to a level that maybe has not yet been reached. If this is the case, it would become an attractive selling point for going with an NVIDIA card over an ATI option -- but ATI might have a trick or two up a sleeve as well.