Changing the camera

I know I have seen this in a tutorial or here in a post but I have seached and cannot find it. How do you change the camera in the game engine.

To explain in more detail:

Supose I had a character that had a walk cycle attached. I wanted three view that the user could choose with a key stroke. Say a first person perspective looking out of the characters face, a third person perspective looking from above and behind the character, and a “tracking” perspectve that would be like a security camera in the upper corner of a room that would track the character wherever he moved about in the room but the camera itself would not move.

How could I switch between these three camera views? I know it would involve a python script and some properties. That much I recall from whoever posted the tutorial. But I cannot find it at all. Just to be clear this is for the GAME ENGINE not in a blender created animation.

in the ‘scene’ actuator there is a change camera option.