Art of Blender
The Art of Blender is full of inspiring renderings from Blender artists around the world.
In this Blender 2.5 video tutorial we will be going over creating shape keys, and then talk on how to apply drivers to the shapekeys so that the armature can control the them.
Homework: After completing the video, I noticed that if you rotate the arm beyond a certain point, the shapkeys disappear. I spent a bit of time trying to dig up this bug, but if you are up for some homework, post your findings below and lets work to figure that one out.
Note: this tutorial uses the official Blender 2.5 Alpha 1 release.