Under Mac OS 10.6.6, we can quickly access the desktop by simultaneously pressing Fn + F11 . But we can also configure the system to access the desktop by pressing a single key as the right command key (cmd), or better yet just passing the mouse over a corner of the screen.
To do this:
Click on the block located in the upper left corner and select System Preferences> Exposé and Spaces "
Under "Active Screen Corners" are 4 options, open the one in the corner and use the drop down menu to select the item to be accessed, for example on the right lower left and select "Desktop"
Thereafter to access the Desktop just pass the mouse over the bottom right corner of the screen