$arr = array(
     array('id'=>1, 'pid'=>0, 'name'=>'Comment 1'),
     array('id'=>8, 'pid'=>0, 'name'=>'Comment 2'),
     array('id'=>9, 'pid'=>0, 'name'=>'Comment 3'),
     array('id'=>10, 'pid'=>0, 'name'=>'Comment 4'),
     array('id'=>11, 'pid'=>0, 'name'=>'Comment 5'),
     array('id'=>2, 'pid'=>1, 'name'=>'Comment 1.1'),
     array('id'=>3, 'pid'=>1, 'name'=>'Comment 1.2'),
     array('id'=>6, 'pid'=>1, 'name'=>'Comment 1.3'),
     array('id'=>4, 'pid'=>2, 'name'=>'Comment 1.1.1'),
     array('id'=>5, 'pid'=>2, 'name'=>'Comment 1.1.2'),
     array('id'=>7, 'pid'=>2, 'name'=>'Comment 1.1.3'),
     array('id'=>12, 'pid'=>8, 'name'=>'Comment 2.1'),
     array('id'=>17, 'pid'=>8, 'name'=>'Comment 2.2'),
     array('id'=>14, 'pid'=>9, 'name'=>'Comment 3.1'),
     array('id'=>13, 'pid'=>12, 'name'=>'Comment 2.1.1'),
     array('id'=>16, 'pid'=>13, 'name'=>'Comment 2.1.1.1'),
     array('id'=>15, 'pid'=>14, 'name'=>'Comment 3.1.1'),
     );
		foreach ($arr as $row){
		$new_arr[$row['pid']][]=$row;
		}
		function my_sort($data, $parent = 0)
		{
			$arr = $data[$parent];
			foreach ($arr as $row){
  			echo '<div id="cat"><strong>Категории</strong></div>
        <div id="catMenu" class="catMenu"><ul>';
        	echo '<li><a href="#">',$row['name'],'</a></li>';
			if(isset($data[$row['id']])) my_sort($data, $row['id']);
			echo '</ul></div>';
		}
		my_sort($new_arr, 0);