The model-view-controller, commonly referred to as MVC, is an industry standard solution to a long time problem in software. For years, software architects have been trying to find ways to cleanly separate the user interface from the business logic from the data access details. MVC provides a theorhetically simple solution to this problem. The MVC pattern was originally developed in Smalltalk and was made wildly popular by the Java community. I will not be able to give the background of MVC the in-depth converage it deserves so please, take the time to Search on MVC. FWIW, I did put a little background on MVC in the MVCnPHP package in CVS.
Before continuing on, be sure you understand what MVC is. I'll demonstrate the details of how MVCnPHP through the sample application.