The update includes:

• Adds support for the new GeForce GTX 275 GPU.
• Adds support for Ambient Occlusion – the newest NVIDIA Control Panel feature to offer enhanced 3D gaming realism exclusively to GeForce GPUs.
• Adds support for CUDA 2.2 for improved performance in GPU Computing applications. See CUDA for more details.
• Expands GPU hardware acceleration for the NVIDIA Video Encoding library to GPUs with less than 32 cores. Applications using this library include CyberLink PowerDirector 7, Nero Move it 1.5, Loilo SuperLoiloScope MARS, and CyberLink MediaShow Espresso.
• Accelerates performance in several 3D applications. The following are examples of improvements measured with Release 185 drivers vs. Release 181 drivers (results will vary depending on your GPU, system configuration, and game settings):
  • Up to 25% performance increase in The Chronicles of Riddick: Assault on Dark Athena
  • Up to 22% performance increase in Crysis: Warhead with antialiasing enabled
  • Up to 11% performance increase in Fallout 3 with antialiasing enabled
  • Up to 14% performance increase in Far Cry 2
  • Up to 30% performance increase in Half-Life 2 engine games with 3-way and 4-way SLI
  • Up to 45% performance increase in Mirror’s Edge with antialiasing enabled
• Automatically installs the new PhysX System Software version 9.09.0408.
• Supports GeForce Plus Power Pack #3. Download these FREE PhysX and CUDA applications now!
• Numerous bug fixes. Refer to the release documentation notes.
• Users without US English operating systems can select their language and download the International driver here.

You can grab the 32 bit drivers here, or the 64 bit drivers here.