A handy little utility has cropped up called MagicPrefs. This menubar application brings some extra functionality and configuration options to the Magic Mouse.
Options for various clicks, taps, swipes, pinches, and the ability to increase the tracking speed by an extra 200% are available. Gestures can be mapped to call Spaces, Expose, Dashboard, etc.
I installed the app and played with it for about 20 minutes. It all seemed to work well but I ended up uninstalling it because I didn’t think the functionality warranted the extra menubar icon.
An application like this should be in System Preferences, where it belongs.