In the wake of a school reform in which Quebec primary and secondary school teachers are asked to revise their teaching practices to ground them into a socio- constructivist perspective as well as school directors who are asked to put into place collaborative management practices, an action research project has been launched in order to assess action research specific contributions on school personnel' professional development. This research project belongs then to those few research studies that look at professional development not as a series of stages one goes through during his career but rather as an exploration process that brings the person to look at his beliefs, values, to examine his attitudes (Van den Berg, 2002) and work upon them to become a better professional. The approach to professional development could then be qualified of phenomenological and subjective that holds a strong collaborative dimension because it is done with the support of colleagues with whom the persons share general professional concerns and which belong to the same community of practice (Lave and Wenger, 1991). Started in January 2004, two groups of school personnel working at high school level and, later on, one group of pedagogical advisors, have been organized. Those people have started conversations dealing with their own concerns regarding their practices in order to adjust them to the reform guidelines. A total of 23 persons, belonging to three groups, are involved in this research. An important assumption on which this research is based is that in order for deep and systemic changes to take place, it is important to understand the concerns people might have regarding the situation as well as the images they hold of their professional roles and responsibilities (Fullan, 2001; Van den Berg, 2002; Windschitl, 2002).Working through such a process of observation-action-reflection, called for by the action research design (Dolbec and Clement, 2004; Savoie-Zajc, 2001) during those 18 months, how do the school personnel position themselves and what is their assessment of the whole process? A first observation that can be made is that members of those three groups have started to recognize the strengths they and their colleagues have. They also realized that professional development is not a matter of taking courses on different topics but it rather starts with their own positioning in their own career and the assessment they make of its direction. They see action research as an appropriate strategy to engage into lifelong learning because it is grounded into their daily professional concrete problems and concerns. A sense of a community in which members can share ideas, concerns, exchange thoughts and pedagogical materials has emerged. They have gone from belonging to a community of practice (Lave and Wenger, 1991) to sharing ideas with a learning community (Orellana. 2002) where there is a collaboration among the members to support each person to become a better teacher, a better school director, a better pedagogical advisor so that the students in their schools are succeeding in their learnings.