Learning and teaching languages in an online environment is one of contemporary education's great challenges. The challenge is made particularly difficult because language learners benefit from a social constructivist approach in which individual learners learn by doing together - negotiating meaning in collaborative interaction. The open source revolution in technology has opened up the possibility of communal efforts to develop technological solutions to such pedagogical challenges. This volume brings together reports from the Covcell Project which developed collaborative tools for the learning management system, Moodle, with papers relating to a range of other tools for online language teaching, in a number of domains including language for special purposes, foreign language equivalency certification, cultural learning practices and oral skills development.