Daniel Gies posted 8 videos so far in his free series on character animation in After Effects. He discusses bones for puppets, sliders to control a rigged character, rigging multi-layered characters (in 3 parts), rigging clothes, and basic head rotations using 3D layers, distortion mesh & expressions in After Effects.

For more resources on character animation in AE, see Animate a character in After Effects at AE Portal (especially the links to Todd Kopriva's references and breakdowns on other tutorials).

See also Learn How to Rig and Animate a Character and Create your Own Odyssey Day 1 and Day 2 by Marcin Zeglinski, and Advanced 2D Cartoon Lip Sync Animation – AE Premium by Dave Scotland here at AEtuts+.

Here's a sample of the new stuff by Daniel Gies (also on YouTube):