$this->set('channel',  array (
          'title'               => 'POSTS RSS',				
          'link'               => 'http://www.yourdomain.com/',
	  'description'  => 'Posts RSS'));


echo $rss->items($posts, 'transformRSS');
			
function transformRSS($posts) {
	return array(
	'title'       => $posts['Post']['title'],
	'link'        => array('action' => 'view', $posts['Post']['id']),
	'guid'        => array('action' => 'view', $posst['Post']['id']),
	'description' => $posts['Post']['body'],
	'pubDate'     => $posts['Post']['created']
);
}