How to Run an Application in Full Screen in Mac OS X Lion
You can maximize the viewing and working areas of an application by running that application in full-screen mode. When you switch to full-screen mode, Mac OS X Lion hides the menu bar, the application’s status bar, the Dock, and the top section of the application window (the section that includes the Close, Minimize, and Zoom icons). Mac OS X then expands the rest of the application window so that it takes up the entire screen.
You must be running Mac OS X Lion to use full-screen mode. Note, too, that not all programs are capable of switching to full-screen mode.
To run an application full screen
Click Enter Full Screen.
You can also hold down Option and click the Zoom button.
Mac OS X expands the application window to take up the entire screen.
To exit full-screen mode, move the mouse up to the top of the screen to reveal the menu bar, click View, and then click Exit Full Screen.