I have been looking at this project for quite some time, but I have only begun to explore the real potential here.
Over at Sloodle and a more recent project to port it over to Open Sim, they are marrying Moodle to a 3d virtual environment in which teachers can ask for students to create “real” learning objects and assess their learning through the use of avitars. So far, it really is only accesible to people who are already familiar with both administrating Moodle and playing with objects in Second Life. I think that the real potential will come when it is more available to the average teacher to set up classes and assignments.
I really do see a future where students can choose to create buildings to understand archetechture and math, create tutorials for writing that could walk through, and simulations to demonstrate a science concept. This isn’t too far off, and I think that the more people who experiment with it, the more likely it will be to happen soon.