I was recently reminded of the fantastic 2001 PBS/NOVA series Evolution, which was released in tandem with Carl Zimmer's book, Evolution: The Triumph of an Idea.

The whole series is great, but episode 6, The Mind's Big Bang, was my favorite. And this segment in particular, starting around the 2:15 mark, featuring Andrew Whiten. I think it's the best video explanation of the "Sally-Anne" test I've yet seen, and clearly explains some of the key theory-of-mind differences between humans and non-human animals.

Also, you can't beat a science documentary narrated by Liam Neeson.

(Here's a link to a Youtube playlist for the entire episode, in order.)