Mac OS X only: Freeware application Warp adds a preference pane to your System Preference that enhances Leopard's virtual desktop tool, Spaces, so that you can switch between spaces using just your mouse. After you've installed and enabled Warp, move your mouse to the edge of the screen to switch to the adjacent space. If you've enabled the "Click screen edge to Warp" option, Warp even provides a preview of the space you're about to switch to. Click the preview and you're there. Warp is freeware, Mac OS X only.