NVIDIA has released ForceWare 158.42 beta drivers for use with Windows Vista.

Release Highlights:

-Updated May 16, 2007 - Replaced driver kits with new one that properly report the driver version as 158.43. The previous kits from May 15 reported the driver as 158.42.
-Add support for GeForce 8600, 8500, 8400, and 8300 GPUs.
-Improved 3D performance for single GPU and NVIDIA SLI
-Add support for NVIDIA SLI on DirectX 10
-Numerous game and application compatibility fixes (see below for some of the top issues)
-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 GeForce 6/7/8 series GPUs
-DirectX 10 support for 8 series GPUs
-OpenGL support for GeForce 6/7/8 series GPUs
-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