Here is a very nice set of tutorials made by Katana31 teaching the basics on the Valve FacePoser tool. Just a quick sidenote, the FacePoser only works in Windows XP. It doesn’t work in Windows 7 or Windows Vista.
I apologize for the language in these videos. I didn’t make them. They are the best FacePoser tutorials I’ve seen however.

Faceposer Tutorial 1: Basic Lipsynching

Faceposer Tutorial 2: Choreography and Hammer (pt 1)

Faceposer Tutorial 2: Choreography and Hammer (pt 2)

Faceposer Tutorial 3: Lipsynching through “Karaoke”

Faceposer Tutorial 4: Gesture Manipulation I

Faceposer Tutorial 5: Team Fortress 2