Sub Navigation in Sidebar

Got it working. This is the final code (pulled from http://cssglobe.com/post/5812/wordpress-find-pages-top-level-parent-id with little modification)

<?php

if ($post->post_parent) {
    $ancestors=get_post_ancestors($post->ID);
    $root=count($ancestors)-1;
    $parent = $ancestors[$root];
} else {
    $parent = $post->ID;
}

$children = wp_list_pages("title_li=&child_of=". $parent ."&echo=0&depth=1");

if ($children) { ?>
<ul>
<?php echo $children; ?>
</ul>
<?php } ?>