Click here (ppt presentation).
It’s a good companion to the Overly Simplistic Guide to Internet Video. If you’re hankering for a good overview of what Codecs and Containers are after watching the simple guide, I recommend browsing through this.
You could of course work with Rhozet for trancoding software, or if you’re a Java developer and came here, you can use Xuggle for free. Your call really.