Try this:

function OnGUI () {
    if (GUI.Button (Rect (10,10,150,100), "I am a button")) {
        transform.Translate (0,10,0);
    }
}

That will move your camera from point a to point b instantaneously. All you have to do is put it on your camera. On the press of a button, it will move from where it is now to wherever you specify in this line:

transform.Translate (0,10,0);.

Hope this helps!