MVC stands for Model - View - Controller, and is a design
pattern independent of Servlet/JSP technology. It represents a way of building systems with three types of demarcated component: the Model, the View and the Controller. A Model is typically data, in the servlet/JSP world it could be a JavaBean which represents a row in a database table for example. The model does nothing more than hold data. A View is a component which can display Model components, and in the Sevlet/JSP world it is probably closest to a JSP (assuming the JSP contains only display logic). The Controller is the part which (it could be considered) handles navigation through the application, and would probably be a Servlet. Again, it would contain no data and no GUI code (i.e. no Model or View).
MVC pre-dates JSP/Servlet technology by some considerable time, and its a good idea to try and understand it independently of those two technologies. One of implementations of MVC in the
Java world is Swing, and there is a good explanation of this here
http://www.javaworld.com/javaworld/jw-04-1998/jw-04-howto.html. In the
J2EE world
Struts, is the most common implementation. It might help you to look at how this works.
(One small note, you can't have a proper MVC implementation as a WebApp - MVC requires two way communication to the view (i.e. changes in the model will be transmitted to the view) but this isn't possible due to the restrictions of HTTP)