Hi,
http://code.google.com/apis/maps/articles/phpsqlajax_v3.html
I spent quite a while trying to get this work, and only succeeded once
I found a typo and corrected it.
The first few lines of the 'downloadURL' call are different to the
document version of the same information.
downloadUrl("phpsqlajax_genxml.php", function(data) {
-->var xml = request.responseXML;<--
var markers = xml.documentElement.getElementsByTagName("marker");
SHOULD READ
var xml = data.responseXML;
Hope this can be updated and help people out.
Pete