If you recently got a Magic Mouse either because it came with your new Mac or because you got excited by the hype and bought one, only to find that the dratted thing is missing the third and fourth buttons which you had so cleverly bound to Expose and Spaces, there is good news. A free application calledMagicPrefs lets you not only add this functionality to the Magic Mouse but lets you define gestures and perform other kinky mods that should be worth a lot more than the millions that Apple paid to acquire Lala.

UPDATE: TUAW has a pointer to another free tool called BetterTouchTool.