Google Maps custom tile overlay

gistfile1.js

// Set up the copyright information
// Each image used should indicate its copyright permissions
var myCopyright = new GCopyrightCollection("© ");
myCopyright.addCopyright(new GCopyright('Demo',
  new GLatLngBounds(new GLatLng(-90,-180), new GLatLng(90,180)),
  0,'©2007 Google'));

// Create the tile layer overlay and 
// implement the three abstract methods                 
var tilelayer = new GTileLayer(myCopyright);
tilelayer.getTileUrl = function() { return "../include/tile_crosshairs.png"; };
tilelayer.isPng = function() { return true;};
tilelayer.getOpacity = function() { return 1.0; }

var myTileLayer = new GTileLayerOverlay(tilelayer);
var map = new GMap2(document.getElementById("map_canvas"));
map.setCenter(new GLatLng(37.4419, -122.1419), 13);
map.addOverlay(myTileLayer);