The University of South Florida screencast teaches you how to switch applications in Mac OS X. The application switcher gives you a quick way to switch through the running programs on your computer. To do this, simply press Command + Tab. You can keep pressing Tab to switch to another program. You can also use the application switcher to quit a program. When it is selected in the application switcher, press the Q key on your keyboard. You can also use the mouse to switch between programs, while the application switcher is active.