Warp This preference pane allows you to use your mouse to switch between Spaces instead of using the keyboard.
Warp allows you to view a live preview of a specific space by moving the mouse to the edge. This allows you to see what is in another space before you switch to it. Clicking on the preview will take you to that space. This feature can be enabled by selecting the option "Click screen edges to Warp" from Warp's preference pane.
Warp is free to use, but donations are greatly appreciated and help in support and development.