The purpose of this study was to make interns-central members who directed a change the nature of the conception of professional development in an online peer-led dialogue. My focuses were what pedagogical aspects in an online peer-led dialogue contributed to intern's professional development (i.e., professional knowledge development and professional identity formation), how an online peer-led dialogue could create new pedagogical discourses in relation to teacher's professional development, how interns took different perspectives and created new images of teacher, how this online peer-led dialogue promoted deepening understanding of the practice of teaching, and how social transformation and teachers empowerment were undertook in dialogue. In terms of these research purposes, the research was conducted an online discussion forum in a rural area of Central Pennsylvania during the 2008 academic year. A research method used in this study was participatory action research, which could bring about critical consciousness through dialogic interaction, changing the nature of learning knowledge about teachers and the role of teachers, and teacher empowerment. Data collection was from written dialogue from an online discussion forum, forum design, and activity reports. Data analysis was focused on interns developed their critical consciousness through dialogic interaction among other interns, whether such critical consciousness contributed to intern's empowerment and constructing critical selfhood. By conducting this research, I discovered that online peer-led dialogue had a great potential which made possible for interns to re-discover a meaning of professional development and to construct critical selfhood. I also discovered that not all of interns could have critical consciousness toward their professional knowledge development and professional identity formation. Despite some unprecedented consequences and results, online peer-led dialogue brought about the possibility of envisioning a new way of a teacher education from a professional development school's sense. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]