Active record where/or_where question?

[eluser]JasonS[/eluser]
This is what I have at the moment.

Code:

$this->db->where('id', $id);
$this->db->or_where('winner', $this->session->userdata('id'));
$this->db->or_where('author', $this->session->userdata('id'));

I want to look for the following

id is equal to $id
where user is either winner or author

How do I do this with the active record class?