This thesis provides an introduction to an advance in technology-aided instruction. Most of the research in this area has focused on PowerPoint® based applications or white board-centered electronic ink applications with the capability of broadcasting slides, ink annotations and so forth, used for presentation or classroom lectures. But these tools lack the capability of annotating on any kind of applications with active content playing (a movie or a simulation, for instance) in the background. Additional useful, but currently unavailable functionality would include the capability of broadcasting the presentation information, which can further consist of lecture slides, ink annotations, video of the desktop screen activity, or any other application program that might be used to demonstrate a concept or illuminate an idea. Therefore, the current research attempts to provide these facilities with a new tool, WriteOn. WriteOn improves both the presentation of information and the interactivity in classroom instruction, because it gives the instructor the ability to ink annotate on any application by using a virtual transparency surface, called electronic vellum or simply eVellum, which in effect resides on top of all desktop window applications. The instructor can enable the vellum at any point during the lecture and write on it to draw diagrams, make notes, emphasize points, or otherwise elucidate the presentation content. The instructor can also pierce the eVellum in order to switch to different applications, modify an applications parameters or operating values, or otherwise manipulate an operating program as part of a classroom demonstration or discussion. These features allow the instructor to demonstrate the dynamic operation of any application, which is an improvement on a static PowerPoint display of a program's operation. With WriteOn, the instructor can save the ink annotations along with desktop screen activity over an interval of time as a movie file and later make this file available to students. Alternatively, the instructor can transmit to the students the presentation information along with ink annotations in real-time so that the students can make their own notes on top of information being produced by the instructor. Thus the tool can be used to enhance the interactive lecturing process and help students to develop good note-taking processes and habits. WriteOn is also capable of saving the voice of the instructor, provided there is an audio device attached to the instructor's Tablet PC. However, broadcasting the instructor's voice is not yet fully supported. The WriteOn tool was developed using Microsoft's technologies: Windows Media Encoder® and DirectShow of DirectX®, as well as Microsoft's ConferenceXP API to achieve streaming of the presentation information. The first chapter explains the need for computer tools used for effective teaching purposes. The second chapter presents the architectural and technical details of WriteOn. Chapter three describes the architecture of the WriteOn tool. Chapters four through six explain the major software components of the system and also give the pros and cons of the DirectShow and Windows Media Encoder technologies. The seventh chapter provides an explanation of the usage of the tool by instructors and students. The eighth chapter presents the experiences of the instructors and students using the WriteOn tool in the classroom and concludes with a discussion of future work in this area. The Appendix V provides a developers guide for those who might like to expand on this open source code. / Master of Science