You can use the loader with a couple of lines of code.
<script src="http://gmaps-utility-library.googlecode.com/svn/trunk/loader/release/loader_packed.js" type="text/javascript"></script>
google.load("maps", "2"); google.setOnLoadCallback(mapsLoaded); function mapsLoaded () { if (google.maps.BrowserIsCompatible()) { map = new google.maps.Map2(document.getElementById("map")); map.addControl(new google.maps.SmallMapControl()); map.setCenter(new google.maps.LatLng(48.25, 11.00), 4); map.enableDoubleClickZoom(); google.extensions.maps.load("markermanager", "x", {uncompressed: true, callback: doWeatherDemo}); google.extensions.maps.load("dragzoom", "x", {callback: addZoomer}); google.extensions.maps.setOnloadCallback(function () {alert("All Libraries Loaded.");}); } } function addZoomer () { map.addControl(new google.extensions.maps.DragZoom.Control()); } function doWeatherDemo () { var IMAGES = [ "sun", "rain", "snow", "storm" ]; var ICONS = []; function getWeatherIcon() { var i = Math.floor(IMAGES.length*Math.random()); if (!ICONS[i]) { var icon = new google.maps.Icon(); icon.image = "../markermanager/examples/images/" + IMAGES[i] + ".png"; icon.iconAnchor = new google.maps.Point(16, 16); icon.infoWindowAnchor = new google.maps.Point(16, 0); icon.iconSize = new google.maps.Size(32, 32); icon.shadow = "../markermanager/examples/images/" + IMAGES[i] + "-shadow.png"; icon.shadowSize = new google.maps.Size(59, 32); ICONS[i] = icon; } return ICONS[i]; } function getRandomPoint() { var lat = 48.25 + (Math.random() - 0.5)*14.5; var lng = 11.00 + (Math.random() - 0.5)*36.0; return new google.maps.LatLng(Math.round(lat*10)/10, Math.round(lng*10)/10); } function getWeatherMarkers(n) { var batch = []; for (var i = 0; i < n; ++i) { batch.push(new google.maps.Marker(getRandomPoint(), { icon: getWeatherIcon() })); } return batch; } var mgr = new google.extensions.maps.MarkerManager(map); mgr.addMarkers(getWeatherMarkers(20), 3); mgr.addMarkers(getWeatherMarkers(200), 6); mgr.addMarkers(getWeatherMarkers(1000), 8); mgr.refresh(); }