Although nearly every college offers a major in computer science, many computer science teachers at the secondary level have received little formal training. This paper presents details of a project that could make a significant contribution to national efforts to improve computer science education by combining teacher education and professional development. A computer science endorsement program will prepare preservice teachers in: basic skills and concepts, programming, algorithm design, computer system components, data bases, and social issues related to computer use. A series of professional development workshops will improve the content knowledge of current teachers, enabling them to teach computer science concepts and information technology fluency.