Apple released an update for owners of NVIDIA (unibody) MacBooks, MacBook Pros and MacBook Airs.
This update improves cursor movement when using the Apple Mini DisplayPort to Dual-Link DVI adapter with the Mini DisplayPort enabled MacBook Air, MacBook and MacBook Pro.
It also improves playback of HD video running on systems with NVIDIA GeForce 7300 GT or GeForce 9600M graphics.
The update should be available in your Mac OS X software update.