var gmap = null;

// Defina a icon
    icon = new GIcon();
    icon.image = "http://www.asap.be/App_Styles/Images/vlagje_groot.png"; // URL of the image
    icon.iconSize = new GSize(25, 25); // sice
    icon.iconAnchor = new GPoint(0, 0); // Place of icon
    icon.infoWindowAnchor = new GPoint(10, 17); // place of information

function showAddress(htmlinfo, lat , lng)
{
    var point = new GLatLng(lat, lng)
    var marker = new GMarker(point, icon);

    gmap.addOverlay(marker);
    GEvent.addListener(marker, "click", function()
        {
            marker.openInfoWindowHtml(htmlinfo);
        }
    );
};