activating a Camera Using a Toggle Button

hey, i cannot seem to make this script work,, can anybody help me, here is the code

var camera: Transform;

var showMap = false;

var xAxis : int;

var yAxis : int;

function Start()

{

camera.enabled = false; // hide it

}

function OnGUI()

{

showMap = (GUI.Toggle (Rect (xAxis, yAxis, 100, 20), showMap, "Map"));

camera.enabled = showMap;

}

All I want is for the camera to activate and deactivate When i hit the Toggle Button Could somebody help ??

Thanks