If you have an Apple Magic Mouse and like many users think it’s way too slow to track (and consequently want to throw this thing into a wall), here is the work around:
MouseZoom for MacOSX
benh57.com/mousezoom.html
The mouse is especially slow if you are using multiple monitors or a bigger 27" or 30" 2560x1600 monitor.
I have mine set to 8. The maximum the stock control panel can do is 1.something.