Yesterday NVIDIA released a new set of beta drivers for Microsoft Windows Vista, v 158.18. The drivers supports the GeForce 6, 7 and 8 series (not the mobile ones).
Apart from a number of bug fixes and improvements (to the NVIDIA Control Panel, improved WMV playback quality and 3D performance) the new interesting feature is the PureVideo HD support. But there are numerous things for NVIDIA to fix, jus read the Release Notes.