Web2.0 is a conceptual framework that aims at enhancing the World Wide Web with semantic and social functionnalities. For this framework to fully develop, there is a need for concrete applications in different domains. This paper presents an effort to instanciate the Web2.0 concepts in a teaching/leanring context. An ontology based collaborative multimedia annotation tool that features pedagogical functionnalities is presented. An original approach to design software based on ontologies is used. A pedagogical scenario, from the KPLAB European project, that makes use of the tool to train medical staff to handle pediatric surgical operations is presented.