Exposé is a convenient way to move around between open documents.
There are three function keys associated with Exposé.
F9: Shows all the active windows that are not hidden. Use the mouse to select the application you want to jump to.
F10: Highlights the current active window. Move through all the active windows by pressing TAB.
F11: Moves all active windows off the screen revealing the desktop.
A quick way to move through active applications is to press and hold the COMMAND key, then press TAB. A iconic view of all active applications appears. Move through the list by continuing to hold the COMMAND key and repeatedly pressing TAB.