Newbie file upload question

Hi,
Very new to CakePHP and my first post here, I am loving Cake so far but have run up against a small hurdle.
Can anyone point me in the direction of instructions on creating a form with a file upload field? It's for a registration form where the user uploads normal stuff (name, address, etc...) and an image or logo of their company.
From what I've seen of Cake so far I think it should be simple enough but I can't work it out, can anyone help?
Paul