Ciao, ho provato per curiosita' .... mi son copiato il tuo xml e l'ho messo pero' allo stesso livello di index.php(mio file principale dove includo tutto)

Ho modficicato giusto2 cose per comodità e cosi' nel mio alert vedo tutti i valori (title image e position)

codice:
 $(document).ready(function()
{
 var desktop=Desktop("test.xml");
});

//TODO Desktop object
 Desktop=function(){
  var icons=null;
  function loadIcons(xml)
  {
     var foundIcons=new Array();
     //Finds every Icon occurrence into xml config file and loads them as Icon objects into foundIcons collection array
     $(xml).find("Icon").each(function()
     {
        foundIcons.push(Icon($(this)));
     });
     //Load icons into Desktop object's icon array
     icons=foundIcons;
  }
  //Init desktop
  $.ajax({
    type: "GET",
	url: 'test.xml',
	dataType: "xml",
	success: function(xml) { 
	   loadIcons(xml);
    }
  });
 };

//Icon Object (module pattern model)
Icon=function(iconXMLEntry){
  var id=iconXMLEntry.attr('id');
  var title=iconXMLEntry.find('title').text();
  var image=iconXMLEntry.find('image').text();
  var position=iconXMLEntry.find('position').text();
  alert(title+ ' '+image+ ' '+position);
  
}