Sloodle is an Open Source project which aims to develop and share useful, usable, desireable tools for supporting education in virtual worlds, making teaching easier. Through engagement with an active community of developers and users, the Sloodle project hopes to develop sound pedagogies for teaching across web-based and 3D virtual learning environments. Sloodle integrates the Second Life multi-user virtual environment and the Moodle learning-management system.
You can find more details on the project and technical information on the development status on the Sloodle Wiki, while the source code is available on Google Code, along with the issues tracker.
You can also visit the Sloodle project in Second Life (currently also in the process of re-modelling!), here: