Toronto-based Bump Technologies Inc, better know by their product name - BumpTop - recently announced multi-touch gesture support for their desktop enhancement software (Read TechCrunch's review here). It requires a touch capable machine running Windows 7 - while I don't have that yet...I'd try dropping by Bump's office and getting a first-hand experience and reviewing it in detail (Or lets just say I can't wait to try this thing out! :P).
BumpTop has taken multi-touch gestures beyond simply moving or selecting things on a screen to actually using it to organize your desktop - from visually stacking files and folders and "moving" around on your desktop by zoom/pan, to even cropping images. Check out their demo video: