Switching cameras?

Hello, I know this is kind of a newbie question, but how in scripting would I make it so when you push a button, it disables one camera, and enables another?

Im making a basic house design with unity and want to be able to switch from first person to birds eye :)

thanks kris

 var camera1 : Camera;
 var camera2 : Camera;

  function Start()
                {
                camera1.enabled = true;
                camera2.enabled = false;
                }

  function OnGUI()

                {

              if(GUI.Button(Rect(10,10,50,20),"button"))

               {

               camera2.enabled = true;
               camera1.enabled = false;

               }

               }