Today a plethora of multimedia, hyperlink software and hardware components are available, as well as teleconferencing systems supporting collaborative work. However, few systems are easy for people to use for real applications such as support of remote instruction. Most importantly, none of these tools scale to use by more than a few users simultaneously. We describe our vision for a system which will support interactive remote instruction (IRI) to support college-level education across spatial boundaries in a manner largely transparent to students and faculty. We have implemented a prototype of this system which has been used to evaluate both the user-interface design and performance requirements. The goal is to have a user interface which models most of the interactions which occurs in a regular classroom. A key focus in this paper is the assessment of system requirements necessary to support large classes. That means that multimedia tools must support O(10), rather than O(1), simultaneous users and user-system interaction protocols must be effective and accepted by students and faculty with diverse backgrounds and computer sophistication.