According to a very trustworthy source, NVIDIA are set to release a new forceware driver for the Windows Vista Feb CTP release. The driver version is 87.15 and should fix some very annoying lag issues that beta testers are having with the default WDDM (Microsoft) driver.
The previous forceware release for Vista Beta 1 was pulled from the site shortly after the February CTP release was made available to testers. v75.03 does not work on build 5308 and actually causes the display adapter to not work at all in Vista giving NVIDIA users nothing but a black screen.
More info as it becomes available.
Update: The driver has now been released here