This article describes some Australian research and professional development projects that use classroom video data, and explains some of the positive outcomes, as well as some of the challenges, of these projects. A variety of methodologies have been used to collect, store, retrieve, code, navigate and analyse classroom video data. These include CD-Rom, DVD and web streaming to dedicated software platforms. Video is used to preserve classroom activity so that it can be 'slowed down' to enable detailed examinations of teaching and learning from multiple perspectives, reveal alternatives through comparative analysis, and stimulate discussions about choices related to teaching learning. Several projects that used classroom video data to support and improve teaching and learning in Australia are considered.