NVIDIA has released ForceWare 163.67 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 6, 7, and 8 series GPUs.
-Improved compatibility for Crysis and BioShock.
-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)

Vista 32-bit | Vista 64-bit

NVIDIA homepage