This qualitative case study examined web-based portfolio development in the service of supporting reflective thinking and learning within the innovative context of Professional Development Schools. Specifically, this study investigated the nature of the evidence-based philosophies developed by prospective teachers as the central part of the web-based portfolio task and the ways in which the technology contributed to it. The findings of this study illuminated the participants' understandings about learning and teaching science emphasizing a student-centered approach, connecting physical engagement of children with conceptual aspects of learning, becoming attentive to what teachers can do to support children's learning and focusing on teaching science as inquiry. The way the task was organized and the fact that the web-based format provided the possibility to keep multiple versions of their philosophies gave prospective teachers the advantage to view how their philosophies were changing over time, which supported a continuous engagement in metacognition, self-reflection, and self-evaluation. Built on these findings we suggest that future research be directed in the area of teachers' knowledge and beliefs about science teaching and learning and the kinds of experiences that influence their development. The ways in which technology tools can contribute to supporting prospective teachers in developing personal theories consistent with current recommendations of reform focusing on supporting learning through inquiry should also be explored. (Contains 1 figure and 3 tables.)