This is a video that was prepared by Delta Airlines about their Dispatchers which they call "Flight Superintendents". It does a great job of explaining the functions and daily duties of a dispatcher and how they impact the overall operation of an airline. It also explains the qualifications needed to be a dispatcher and the expectations you should have as a new dispatcher entering into the workforce.
Another great video demonstrating the job functions of a Dispatcher. Also gives real scenarios of in flight emergencies and mechanical problems and how those situations get handled by several different operational groups.
Here is another great video from United Airlines that discusses their Network Operation Center (NOC) which is where the Dispatchers work. It also discusses some of the other personnel inside the NOC.