ciao MacApp,
semplicissimo....

così funziona:

//--------------------------------------------------------------------
Codice PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
    <title>Google Maps JavaScript API Example</title>
    <script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key=ABQIAAAAx5HUbsxvK_8UdhyqrjKYexR7SdOpTdFKzVPOdBwb0Om8HIikYBQM1Cv3nsJPKlyeEWHGPyqKg3LwuQ"
      type="text/javascript"></script>
    <script type="text/javascript">
    //<![CDATA[
    function load() {
    
      if (GBrowserIsCompatible()) {
      
        var map = new GMap2(document.getElementById("map"));
        map.setCenter(new GLatLng(41.895466, 12.482324), 13);
        
        var marker = new GMarker(new GLatLng(41.895466, 12.482324),'');
         GEvent.addListener(marker, "click", function() {
              marker.openInfoWindowHtml('ciao');              
           });              
        map.addOverlay(marker);
      }      
    }
    //]]>
    </script>
  </head>
  <body onload="load()" onunload="GUnload()">
    <div id="map" style="width: 500px; height: 300px"></div>
  </body>
</html> 
//--------------------------------------------------------------------


se in alto inserisco:

//--------------------------------------------------------------------
Codice PHP:
$link = mysql_connect($dbHost,$dbUser,$dbPassw);
$select = mysql_select_db($dbName,$link); 
//--------------------------------------------------------------------

non vedo nulla?!?!??....