Monty Montgomery at xiph.org gives us the first part of A Digital Media Primer for Geeks.
It’s licensed under a Creative Commons Attribution-NonCommercial-ShareAlike (BY-NC-SA) license and there’s a discussion wiki and the entire show was edited completely with free and open source software. You will not only learn a lot about digital media but you’ll get to see it demonstrated for you knowing that everything you see you can do (and more, of course, limited only by your own imagination and will).
Enjoy the freedom.
WebM Format (Vorbis audio + VP8 video):
Ogg Format (Vorbis audio / Theora video / Kate subtitles + Index):