BetterTouchTool makes it possible to make the gestures on MacBooks do everything you want. You can set key commands that should be executed if you do the selected gesture.
BetterTouchTool is based on MultiClutch but it works totally different. So it works on Snow Leopard and does not need installation.
Additionally it introduces a new gesture called three finger tap. The standard behavior for this gesture is doing a middle click, but you can customize it the way you want. This works on Magic Mouse and Macbook Touchpad.
* Three Finger Tap
* Customize Gestures global and app specific
* does not need installation, just start the app and it should work
* set higher mouse speed than possible with apple prefs
* Magic Mouse atm supports: swipe left, swipe right, three finger tap. More gestures will be available soon