[knotty66]

Khan Academy - not sure how far 'post school' it goes though. Try the exercises, definitely good for a refresher at least.

[taliesinb]

Probably not a bad place to start is just iTunes U. There is some pretty cool stuff curated there -- I'm just delving into Andrew Ng's machine learning course.

[taliesinb]

It doesn't go very deep at all -- I've checked. It is pretty wide, though.