NVIDIA has made available a new WHQL approved driver for its GeForce 6, 7, 8, 9, 100 and 200 series cards and ION GPUs, the ForceWare 196.21.
One of the main features of the new release is the added SLI and multi-GPU support for a bunch of popular game titles. These include the Avatar Demo, Battlefield: Bad Company 2, City Bus Simulator, Dirt 2, Ferrari Virtual Race, GREED: Black Border, Mass Effect 2, Mortal Online, Ninja Blade, Operation Flashpoint: Dragon Rising Demo, Planet 51, RUSE, Serious Sam HD and Wings of Prey.
Further to the above is an upgrade to the PhysX system software (now at 9.09.1112) and a bunch of numourous bug fixes which you can learn more specifically about in the supported documentation located at this page.
You can download the drivers for Windows XP, Vista and 7 (in both 32 and 64-bit form) at this page folks.