Here is two links (you've probably all seen them before but...)
These are great examples of what can be achieved in Maya (straight out of the box.....I think).
I'm assuming the techniques used in the above examples are done using blendshapes only.
I would be keen to find out exactly what processes were invovled, e.g (blendshapes, clusters, etc..) HOMEWORK ANYONE????????
I created a head for a UNI project last year (2 minutes of animation) that used the technique from the tut on blendshape from the AW site.
The head that I created used 25 blenshapes (major muscles fully flexed).
I then used SDK (set driven key) to procedually drive facial expressions that used various combinations of these 25 blendshapes. eg. smile used about 6 or 8 blenshapes.
I then used the Trax editor to separate/layer the animation using Maya's character and sub character nodes. i.e.
main head character,
a sub character node for eyes,
eye look at,
mouth and tongue.
What this achieved for me was the ability to perform most if not all facial mannerisms quickly and precisely that was indeed fun to animate.
Will post up some pics of the head (and blendshapes) one day soon.
Mayan elder......only in years.....