If you want to find out some possibilities of virtual worlds for interactive learning, check out the introductory video by Virtual Learning Curve. It gives a good overview of some of the possibilities of Virtual Immersive Environments (VIEs).
For even more interesting and engaging videos go to the Scenes to Watch and checkout some samples and trailers that really point to the power of 3D virtual environments.
Check out the company at Virtual Learning Curve.
Catalog of Recommended Books, Games and Gadgets
Recommended Games and Gadgets