If the available settings in the mouse preference panel aren’t good enough for you, You can adjust the tracking speed via OS X Terminal using the following command:
defaults write -g com.apple.mouse.scaling x.x
Replace x.x with a number between 1 and 5:
defaults write -g com.apple.mouse.scaling 4.5
Use for fast tracking 5.0, and for slow tracking 1.0
Restart your Mac for changes to take effect.
Restore to default setting with:
defaults delete -g com.apple.mouse.scaling