I figure out how to build a podcast feed on CakePHP 1.2. If you are reading this you should already know how to make a normal RSS feeder with CakePHP.

Made podcast is easy but no documented. So, you have a Podcast model wich keeps podcast information, in podcasts_controller.php I wrote a rss() method:

public function rss($username)
{
 $this->pageTitle = $username .' Podcasts';              //bloggerdata                                                                                                                        
  $User = $this->Podcast->User->find(array('username'=>$username), array('id', 'username','name','email', 'name_blog', 'avatar'));

   $channelData  = array('title'         => $username.' Podcasts',
      'link'           => array('controller' => 'blog', 'action' => $username),
                        'description'    => 'Audio from '. $username .' edublog',
                        'itunes:summary' => 'Audio from '. $username .' edublog',
                        'language'       => 'en-us',
                        'copyright'      => 'Chipotle Software, 2008',
                        'generator'      => 'Karamelo Platform',
                        'managingEditor' => 'podcasts@chipotle-software.com',
                        'itunes:owner'   => $username,
                 'itunes:image'   => '/images/avatars/'.$User['User']['avatar'],
                        'itunes:author'  =>  $User['User']['name']
                       );

   $this->Podcast->User->unbindAll();
   $conditions = array('status'=>1, 'user_id'=>$User['User']['id']);
   $fields = array('Podcast.id', 'Podcast.title', 'Podcast.filename', 'Podcast.description', 'Podcast.keywords', 'Podcast.created', 'Podcast.duration', 'Podcast.title', 'Podcast.length', 'Podcast.subject_id', 'Subject.title');
   $order = 'Podcast.created DESC';
   $limit = 12;
   $podcasts = $this->Podcast->findAll($conditions, $fields, $order, $limit);
   $this->set(compact('channelData', 'podcasts'));
}

As you can see I am using $username argument to get user data. You already have a RSS template in APP/views/layouts/rss/default.ctp wich looks like:

echo $rss->header();
 $channel = $rss->channel(array(), $channelData, $items);
echo $rss->document(array(), $channel);

this file is the same to RSS 2.0 feeder, you don't need create another layout file. Now the view file to rss action wich is in APP/views/podcasts/rss/rss.ctp

function rss_transform($item)
{
 return array(
      'title' => $item['Podcast']['title'],
      'guid' => '/files/podcasts/'. $item['Podcast']['filename'],
      'enclosure' => array('url'=>'/files/podcasts/'. $item['Podcast']['filename'], 'length'=> $item['Podcast']['length']),
      'description' => strip_tags($item['Podcast']['description']),
      'pubDate' => $item['Podcast']['created'],
      'itunes:author' => 'Karamelo',
      'itunes:summary' => strip_tags($item['Podcast']['description'])
     );
}
$rss->addNs('itunes');
$this->set('items', $rss->items($podcasts, 'rss_transform'));

The magic is done by addNs (add name space) method wich insert itunes tags...  Voila!  

You can see results here.