It’s called Switcher, and you might already be familiar since it’s been out for a while.
Hint: If you turn off the animation it’ll even work really well on older computers.Download Switcher from Insentient.net
Great Expose Clone for Windows Vista
The market seems to be full of OS X Expose clones, but this is the first one that I've found that not only works really well, but has a ton of customization options.
