function load() {
    var map = document.getElementById("map");
    if (GBrowserIsCompatible()) {
        var gmap = new GMap2(map);
        gmap.addControl( new GSmallMapControl());
        gmap.addControl( new GMapTypeControl());
        gmap.addControl( new GOverviewMapControl(new GSize(100,100)));
        gmap.setCenter( new GLatLng(51.503748, -0.601833), 14);
        var point = new GLatLng(51.503748, -0.601833);
        gmap.addOverlay(createMarker (point, "Slough Meeting House", "Meeting for Worship times: 10.30am every Sunday"));
    } else {
        alert("Sorry, your browser does not support Google Maps. Use the link to streetmap.co.uk instead");
    }
}

function createMarker(point, title, info) {
  var marker = new GMarker(point);
  GEvent.addListener(marker, "mouseover", function() {
    marker.openInfoWindowHtml("<b>" + title + "</b><p>" + info + "</p>");
  });
  return marker;
}

window.onload = load;
window.onunload = GUnload;