Je kunt dit binnen één statement doen door zoiets als dit te doen:
$sXML = download_page('http://remotepage.php&function=getItems&count=100&page=1');
$oXML = new SimpleXMLElement($sXML);
$query = "INSERT INTO tbl_item (first_name, last_name, date_added) VALUES";
foreach($oXML->results->item->item as $oEntry){
$query .= "('" . $oEntry->firstname . "', '" . $oEntry->lastname . "', '" . date("Y-m-d H:i:s") . "'),";
}
mysql_query($query);