As increasing numbers of students with disabilities are placed in regular classrooms, the shortage of rural special educators means that many rural classroom teachers are the primary providers of individualized programming to meet special needs. Since 1994, West Virginia University has been expanding its existing teacher education programs to serve a new and growing population: regular educators seeking additional endorsement in special education. In the Mainstream Practicum Project, these professional personnel (who already have appropriate credentials in elementary or secondary education) will complete all requirements for state teaching certification in one or more areas of special education (and a Master's degree, if desired) via coursework delivered at off-campus centers, plus on-the-job supervision of practicum experiences in their own classroom. Practicum supervision is provided through collaborative peer supervision involving a regular-education cooperating teacher, a special-education cooperating teacher, and a university supervisor. This paper provides a detailed outline of the design of the Mainstream Practicum Project, including project goals and objectives; teacher competencies; program development and delivery (modification of eligibility criteria for practicum participants and supervisors, redesign of practicum procedures and materials, delivery of coursework and practicum experiences); project evaluation plan for formative and summative evaluations; and project integration into the existing special education program. Contains 25 references. (SV)