GDownloadUrl("phpsqlajax_genxml2.php?cp="+ cp, function(data) {
          var xml = GXml.parse(data);    
          alert(xml.getElementsByTagName("marker"));
          var markers = xml.getElementsByTagName("marker");
          
          for (var i = 0; i < markers.length; i++) {
            var name = markers.getAttribute("nom");
            var prenom = markers[i].getAttribute("prenom");
            var address = markers[i].getAttribute("adresse");
            var codepostal = markers[i].getAttribute("codepostal");
            var ville = markers[i].getAttribute("ville");
            var societe = markers[i].getAttribute("societe");
            var tel = markers[i].getAttribute("tel");
            var mail = markers[i].getAttribute("mail");
            var point = new GLatLng(parseFloat(markers[i].getAttribute("lat")),
                                    parseFloat(markers[i].getAttribute("lng")));
            map.setCenter(point,8);
            var marker = createMarker(point, name, prenom, address, codepostal, ville, societe, tel, mail);
            map.addOverlay(marker);
          }
        });

function convert($chaine){

    $avant = "àáâãäåòóôõöøèéêëçìíîïùúûüÿñÁÂÀÅÃÄÇÉÊÈËÓÔÒØÕÖÚÛÙÜ";  
    $apres = "aaaaaaooooooeeeeciiiiuuuuynaaaaaaceeeeoooooouuuu";
    
    $chaine = strtolower($chaine);
    $chaine = strtr($chaine, $avant, $apres);
    
    return $chaine;    
}
[#red]exemple :[/#]
$row['adresse'] = convert($row['adresse']);