NVIDIA has released ForceWare 158.18 drivers for use with Windows Vista.

Release Highlights:

-WHQL Certified Driver
-NVIDIA has a problem when trying to enable NVIDIA SLI using the international driver kit. If you are having problems enabling this feature, please download the U.S. English driver kit.
-Adds support for GeForce 8600 GTS, GeForce 8600 GT, and GeForce 8500 GT, GeForce 8400 GS, and GeForce 8300 GS GPUs.
-Increased performance in 3D applications.
-PureVideo HD support.
-Add support for forcing Vertical Sync in DirectX applications.
-Updated NVIDIA Control Panel with improved user interface (Please see the Release Notes for more details).
-Numerous game and application compatibility fixes.
-This driver supports the following 3D features:
-Single GPU support
-DirectX 9 support for GeForce 6/7/8 series GPUs
-DirectX 10 support for GeForce 8 series GPUs
-OpenGL support for GeForce 6/7/8 series GPUs
-NVIDIA SLI support
-DirectX 9 support for 6/7/8 series GPUs
-OpenGL support for 6/7/8 series GPUs
-DirectX 10 NVIDIA SLI support for GeForce 8800 GPUs will be available in a future driver
-Please read the release notes for more information on product support, feature limitations, and known compatibility issues

Release notes (.pdf format)

Vista 32-bit | Vista 64-bit

NVIDIA homepage