Yes, it's called hot corners. (EDIT: see xUKHCx's post) You can set the corners of the screen to a variety of actions, including the three Exposé actions. Then you flick the mouse to the screen corner and it initiates the Exposé action. So I have mine set something like UL = all windows, LL and LR = application's windows, and UR = desktop. 🙂 It's the only way to use Exposé, my friend. Once you try it, you'll be addicted. 😀