Angie Taylor has a 3rd tutorial, Control Layers in Adobe After Effects for character animation, from her inexpensive introductory training set 2D Character Animation in After Effects.

A control layer is a Null layer linked to an Expression Control effect used to build a rig for easier animation of layers. By the way, this training has a companion set Animated Character Design in Illustrator. You can watch these and other free samples of AE training, including Todd Kopriva's AE FAQ videos, on the Video2brain website.

For more resources on character animation in AE, see Animate a character in After Effects at AE Portal.