NVIDIA has released ForceWare 77.76 Official Beta.

Release Highlights:

-SLI support for GeForce 6600 and GeForce 6600 LE
-New SLI rendering mode (SLI Antialiasing) for increased antialiasing performance
-Broader SLI optimizations and validation for the latest games
-Issues resolved since ForceWare 77.72
-"Overbright" color issue affecting video playback
-GeForce 7800 GTX clock reduction when using extremely cold temperatures to cool the GPU
-For a full list of other issues resolved, please view the driver release notes.
-Microsoft DirectX 9.0c and OpenGL 1.5 support

Note: These drivers are BETA so use at your own risk.

View: Release Notes (.pdf format)

Download: ForceWare 77.76 Official Beta (list of mirrors)