You can use
$this->Session->read('myParam') in your Views files.
But you can't use
As noted here:
The major difference between the Session Helper and the Session Component is that the helper does not have the ability to write to the session.
If you're in the controller, use the Session component. It's included, by default, in all the controllers. It has the Session::read() and Session::write() methods. Check out http://book.cakephp.org/view/173/Sessions for more information.
I believe, if the Session component is like some of the other components, you can use it inside the views. Try just doing $session->read() in your view code blocks. If that doesn't work, try doing a $this->Session->read(...). As a last resort, if none of those work, you can always use the good old PHP $_SESSION, although it's kinda veering outside the Cake framework. However, if you are sure you're not going to use Cake's Session management (and you don't really have to, IMO, as it's little more than a wrapper around $_SESSION), then just know when to properly apply the hack.