Here's a function I came up with to convert an associative array to XML.  Works for multidimensional arrays as well.

<?php
function assocArrayToXML($root_element_name,$ar)
{
    $xml = new SimpleXMLElement("<?xml version=\"1.0\"?><{$root_element_name}></{$root_element_name}>");
    $f = create_function('$f,$c,$a','
            foreach($a as $k=>$v) {
                if(is_array($v)) {
                    $ch=$c->addChild($k);
                    $f($f,$ch,$v);
                } else {
                    $c->addChild($k,$v);
                }
            }');
    $f($f,$xml,$ar);
    return $xml->asXML();
}
?>