NVIDIA has released ForceWare 163.11 beta drivers for use with Windows Vista.

Release Highlights:

-Beta driver release.
-This driver supports single GPU and NVIDIA SLI technology on DirectX 9, DirectX 10, and OpenGL for GeForce 8 series GPUs.
-Improved compatibility for World in Conflict.
-Numerous game and application compatibility fixes. Please read the release notes for more information on product support, feature limitations, driver fixes and known compatibility issues.

Release notes (.pdf format)

Vista 32-bit | Vista 64-bit

NVIDIA homepage