Planet CakePHP

Hi,
can anyone give me an example on how to create Sessions and write data to it. I've seen syntax on how to write data to a session using write command. But how to create a session and retrieve the values in it.

In my application, I have two data, form_id and user_id that needs to be used in all the page requests. So how do I save it as a session variable and use it across the application?

EDIT

function register()
{
	$userId=$this->User->registerUser($this->data);
	$this->Session->write('User.UserId',$userId);
	//echo "session".$this->Session->read('User.UserId');
	$this->User->data=$this->data;
    if (!$this->User->validates())
    {
    $this->Flash('Please enter valid inputs','/forms' );
      return;	
    }

$this->Flash('User account created','/forms/homepage/'.$userId);            

}

How to use the session variable 'User.UserId' instead of $userId in $this->Flash('User account created','/forms/homepage/'.$userId);

And can I use this variable in all my view files,because in all the page requests I also pass the userId?

EDIT 2

I have 2 controllers,user and form. I write the userid to a session variable in the users*_controller. I have a view file called homepage.ctp,whose action is in the forms_controller.* Now how can I use the session variable defined in the users_controller in the homepage? Sorry if I am asking silly questions. I went through the cakebook,but my doubts weren't cleared. I'm also trying trial and error method of coding,so please help me.

EDIT 3

I have a session variable 'uid' which is the user id in the home page action of a controller.

       $this->Session->write('uid',$this->data['Form']['created_by']);

I need the same variable in the design action method of the same controller.
When I give

             $uid=$this->Session->read('uid');
            echo "uid: ".$uid;

the value is not echoed.

Can't I use the session variable in the same controller?