What is Multiple-Camera Shooting?
Several cameras (film or video) are employed on a seta and they record or broadcast a scene. Two outer cameras shoot close shots of the two most active characters on the set whenever it’s needed. A central camera or cameras shoot a wider master shoot to capture the overall action and geography of the scene. This way they also don’t have to start and stop the action and they can do it all in single take. Every camera is set up in a certain way so that different angles and groupings can be captured. Multi camera shooting is used a lot in events such as Graduation, dance recitals, movies and sports. Many of the great movies produced today use the method of multiple camera shooting.

http://en.wikipedia.org/wiki/Multiple-camera_setup
http://wiki.artdirectors.org/~wiki2/index.php?title=Designing_for_Multi_Camera
http://www.videomaker.com/article/9590/