WizMouse gives you the ability to utilize your mouse wheel on non-active windows and more.

When you have WizMouse active, it will send any wheel commands to the window beneath the mouse pointer rather than the one currently focused. You will no longer be required to click the window to focus before being allowed to scroll through it. Optionally, you can also enable mouse wheel use in apps that do not support that function. Additionally, it can reverse the mouse wheel direction (like in OS X Lion "Natural" scrolling).

WizMouse is designed to allow your mouse's wheel to behave in a more productive and efficient manner. Having this augmented mouse wheel capability will be of use when happen to be working with multiple windows eliminating the need for title bar clicking to activate the window before scrolling. And it offers quick enabling/disabling via the systray icon. A nice compact option for using your mouse wheel function to its fullest potential and is also offered in a portable version so you can take the enhancement with you anywhere.