<?php
$string = wp_list_pages('sort_column=menu_order&exclude=79&title_li=&echo=0');
$pattern = '/<li\sclass="page_item(\scurrent_page_item)?">.*href="http:\/\/(.*)"\stitle="(.*)".*<\/li>/i';
$replacement = '<li class="link$3$1"><a href="http://$2" title="$3">$3</a></li>';
echo preg_replace($pattern, $replacement, $string);
?>