List Child Pages

list-chid-pages.php

<?php
/*
	Plugin Name: Steph's Tiny List Child Pages Plugin
	Plugin URI: http://sillybean.net/2010/06/listing-child-pages-with-a-shortcode/
	Description: Lets you list child pages using a shortcode. Also displays child page list by default on empty parent pages.
	Author: Stephanie Leary
	Version: 1.0
	Author URI: http://sillybean.net/
	License: GPL v2 or later
*/ 

// note depth = 0 (no hierarchy)
function scl_child_pages_shortcode() {
   $id = get_the_ID();
   return '<ul class="childpages">'.wp_list_pages( 'echo=0&depth=0&title_li=&child_of='.$id ).'</ul>';
}
add_shortcode( 'child-pages', 'scl_child_pages_shortcode' );
add_shortcode( 'children', 'scl_child_pages_shortcode' );
add_shortcode( 'subpages', 'scl_child_pages_shortcode' );

// note no depth argument (full hierarchy)
function scl_append_child_pages( $content ) {
   $children = '';
   if ( is_page() && ( empty($content) ) ) {
      $id = get_the_ID();
      $children = '<ul class="childpages">'.wp_list_pages( 'echo=0&title_li=&child_of='.$id ).'</ul>';
   }
   return $content.$children;
}
add_filter( 'the_content', 'scl_append_child_pages' );