Face animation is a challenging area of computer graphics and multimedia systems research (Parke, 1996). Realistic personalized face animation is the basis for virtual software agents that can be used in many applications, including video conferencing, online training and customer service, visual effects in movies, and interactive games. A software agent can play the role of a trainer, a corporate representative, a specific person in an interactive virtual world, and even a virtual actor. Using this technology, movie producers can create new scenes including people who are not physically available. Furthermore, communication systems can represent a caller without any need to transmit high volume multimedia data over limited bandwidth lines. Adding intelligence to these agents makes them ideal for interactive applications such as online games and customer service. In general, the ability to generate new and realistic multimedia data for a specific character is of particular importance in cases where pre-recorded footage is unavailable, difficult, or expensive to generate, or simply too limited due to the interactive nature of the application.