This paper describes the expertise that teachers need to acquire in order to facilitate pupils' self-expression with multimedia. The central idea behind the argument is that multimedia is a creative tool for children and that multimedia learning in the near future is expected to be "Learning by Producing." In such a context of creative learning, pupils need to be recognized as multimedia producers. In order to achieve this situation, teachers need to know how to become learning supporters, curriculum developers, and multimedia coordinators, not just instructors. The necessity for teachers to know the typology and features of multimedia expression, and program evaluation are also discussed with some suggestions. The paper contains the following sections: (1) multimedia production by children, including children as multimedia producers, multi-mode expression, and multimedia literacy; (2) a cross-curricular model of multimedia learning, including isomorphic structure and cross-curricular model, learning unit model, and typical multimedia learning projects (e.g., a CD-ROM encyclopedia, children's television station, and Internet newspaper); (3) facilitating roles of teachers, including learning supporter, curriculum developer, and multimedia coordinator; and (4) specific knowledge about multimedia production, including educational typology of multimedia expression, features of multimedia expression, and creativity and spontaneity necessary for multimedia production. Contains 17 references. (Author/DLS)