Mouse Switcher is an interesting Windows 7 tool which allows you to launch and navigate the task-switching Alt+Tab dialog by using the mouse wheel alone.
Once installed, then, you no longer need to reach for the keyboard to access all your open windows. Just move the mouse cursor over the taskbar, spin the scroll wheel, and the Alt+Tab display of open windows will appear. Spin the scroll wheel again to select the window you'd like to open, and move the mouse cursor off the taskbar to switch to it.
This is easy enough, but we did find ourselves wanting to click on an Alt+Tab window icon to select it. Which, in fact, just closed the display and returned us to our previous window. If you feel the same way, though, this is easily fixed: just choose the Configure Mouse Switcher option on your Start menu, clear "Clickless Window Switching", and you'll then be able to switch to any Alt+Tab window with a click.
Perhaps the best aspect of Mouse Switcher, though, is its very unobtrusive nature. It doesn't add yet another icon to your system tray, or install any new background process on your PC. It only uses system resources when you're switching tasks with it (and even then, requires hardly any RAM). And it doesn't replace or turn off your usual Alt+Tab functionality, so you can carry on using the keyboard to switch tasks and it'll work just as it always did.
An easy and lightweight way to switch tasks using the mouse alone