KatMouse Mouse Wheel Enhancer (Windows - Free)
The prime purpose of the KatMouse utility is to enhance the functionality of mice with a scroll wheel, offering 'universal' scrolling: moving the mouse wheel will scroll the window directly beneath the mouse cursor (not the one with the keyboard focus, which is default on Windows OSes). This is a major increase in the usefullness of the mouse wheel.
Another feature involves the wheel button. Since the wheel button is not consistently used in Windows, KatMouse can use it for a kind of task switching: with a click of the wheel button you can push a window to the buttom of the stack of windows that is your desktop, making a recovered window the active window.
Since KatMouse uses functionality only available on the NT line of Microsoft operating systems, KatMouse will run on NT(SP3+), Windows 2000, XP and Vista, but not 9x and ME.
Download at: KatMouse Mouse Wheel Enhancer (Windows - Free)