In this paper, we will outline some results of an NCETM (National Centre for Excellence in the Teaching of Mathematics) funded project that aimed to establish a professional development network with an open-source mathematical software--GeoGebra--in England. During the past few years a large international user and developer community has formed around various GeoGebra-related activities. Most teachers who are currently using GeoGebra have not received professional training in the implementation of the software in their teaching practices, but have begun using it due to their enthusiasm or encouragement by their colleagues. However, research suggests that, for the majority of teachers, solely providing technology is insufficient for the successful integration of technology into their teaching. It has been suggested that adequate training and collegial support boost teachers' willingness to integrate technology into their teaching and to develop successful technology-assisted teaching practices. Thus, in our project, involving nine experienced English teachers, we outlined some priorities for professional development and developing supporting materials for English teachers. (Contains 4 figures.)