1. Introduction
In the past decade, the Internet has spawned many innovations and services that stem from its interactive character. There are numerous indications that the ongoing process of adding mobility to interactivity will transform the role of the Internet and pave the way for yet another set of innovations and services. The convergence of computing and communication is a process that is about to turn phones and mobile terminals into powerful multimedia units. The XML-based Synchronized Multimedia Integration Language (SMIL), for instance, is devised for the distribution of sophisticated multimedia content in a variety of devices, ranging from stand-alone computers to cellular phones [1]. Diverse multimedia applications have flourished with recent advances in hardware and network technology, the proliferation of inexpensive video-capture devices, and widespread adoption of the worldwide web. Video content significantly enhances the learning and communication experience. When properly linked to text, charts and images, video provides the realism, interest and detail not available in other media [2].