Take a look at Shortcourses and see what you think:
They have several free courses.
A Google search turns up lots of prospects, but you would have to check each one to determine if it is free or not.
I have searched online for some decent online (free) photography courses/classes, but have not found any. I saw a piece on yahoo about a great one, but was unable to find it again. At any rate, just googling is not enough. Maybe someone could steer me in the right direction.