An approach to teacher inservice training in the use of computer-based learning is described in this paper, with specific discussion devoted to the development of a videotape training module by the Hertfordshire Advisory Council for Educational Technology (HACET) to demonstrate the role of educational technology, and in particular microcomputers, in the classroom. A general consideration of microcomputers and their applications in educational technology is followed by a detailed account of the design and preparation of the HACET learning module and of the steps involved in preparing a videotape of a classroom microcomputer demonstration. Accompanying the text are five diagrams. (Author/JL)