Cant sort page order

Hi All,

I’m using the following code to highlight which page you’re on:

<?php
	foreach(get_pages('childof=0') as $p) {
	  if($p->post_parent == 0) {
	    $lc = ($p->ID == $wp_query->post->ID) ? ' class="active"' : '';
		echo '<li><a href="'.get_permalink($p->ID).'" title="'.$p->post_title.'"'.$lc.'>'.$p->post_title.'</a></li>';
	  }
	}
	?>

It works well, however, it has stopped me using any plug in to sort the page order and simply shows the page names in alphabetical order. Is there anyway I can alter this?

many thanks