MagicPrefs is a free menubar and preference pane application for OSX which aims to improve the functionality and configuration options of the Apple Magic Mouse.
It features the ability to bind a variable number of finger clicks, taps, swipes, pinch and other gestures to functions like Middle Click , Hold Down Both Mouse Buttons , Spaces , Expose, Dashboard , Recent Applications, Tweet, Read Tweets, Google Reader etc.
Touch Sensitivity implements a single point control for a number of factors impacting the algorithms of the taps, swipes, pinch and other gestures.
Tracking Speed adds the ability to increase the maximum mouse speed by an extra 200%.
Also featured is a real-time display of the fingers touching the surface of the mouse that you can enable to test and monitor the way the mouse sees your input.