This article discusses the effects of the Regional Technology Assistance Program (RETA) on the teaching practices and collegial behaviors of its participants and instructors. It presents findings that suggest that, as a result of their involvement in RETA's ongoing, peer-directed, constructivist-based professional development workshops, teacher participants and teacher instructors have: (1) increased their use of technology in the classroom; (2) increased their use of certain constructivist practices in the classroom; (3) increased their collaboration with other teachers; and (4) assumed more leadership positions. Successful reorientation of teachers from direct instruction to constructivist teaching methods must alter teachers' epistemologies. Professional development, must address the beliefs held by educators and the methods in which they incorporate those beliefs into their teaching as well as deliver effective, new methods of integrating technology and curricula. (Contains 17 references and 8 tables.) (Author)