Nvidia 185.20 beta drivers leaked : Includes ambient occlusion 
MyADSL | by HideInLight | Fri, Jan 2
The drivers are available for Windows XP (32-bit and 64-bit), Windows Vista (32-bit and 64-bit) and Windows 7 build 7000 and can be found here. Saw some comparison earlier using Crysis Warhead to demostrate AO and it looked great. Can't seem to find the link anymore though...
