Wordpress Parent / Children

<div id="leftNavContainer">
<?php
	if ($post->post_parent !== 0) {
		$args = 'child_of=' . $post->post_parent;
		$CategoryName = get_the_title($post->post_parent);
	}
	else {
		$args = 'child_of=' . $post->ID;
		$CategoryName = get_the_title($ID);
	}
	$parent_link = get_permalink($post->post_parent);

	echo"<div class='leftNavInnerContainerHeader'><a href='".$parent_link."'>". $CategoryName ."</a></div>";
	echo"<div id='leftNavInnerContainerBody'>";
		echo"<ul>";
			$children = wp_list_pages($args . '&title_li=&depth=1');
		echo"</ul>";
	echo"</div>";

?>
</div>