These are the materials from my half of the rigging workshop at the Blender Conference 2007.
Slides
Example .blend files
Note: many (perhaps all) of these files require a recent SVN binary of Blender.
Other Stuff
I demonstrated the use of Pencil during my presentation. It can be found here:
http://www.les-stooges.org/pascal/pencil/index.php?id=Home
For Linux users like me, you'll need to compile it from source on your own. Here is a thread that will help you get it to compile:
http://lesstooges.free.fr/pencil/forum/viewtopic.php?id=7