I am using the following code:
<div id="sub_menu">
<?php
if($post->post_parent)
$children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0");
else
$children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
if ($children) { ?>
<ul>
<?php echo $children; ?>
</ul>
<?php } ?>
</div>
To list a submenu of a parent page. I want to try and figure out how to add .first and .last css classes to the menu. Is that possible?