参考：http://www.misty540.net/wp/article_187.html

pp_controller:beforeFilter  内で allow メソッドを使います。

[php]
// homeと test に誰でもアクセス可能
$this->Auth->allow(array(‘controller’ => ‘pages’, ‘action’ => ‘display’, ‘home’));
$this->Auth->allow(array(‘controller’ => ‘pages’, ‘action’ => ‘display’, ‘test’));
[/php]