When I got home from San Diego last night I spent some time playing with the recent updates to OpenCroquet. Since the latest version was released a couple of weeks ago, there have been many updates: the system now seems to run much faster on my Mac and many of the virtual worlds either now work or work better. Give it a try!
I can not imagine a better environment than Squeak and OpenCroquet for teaching children all aspects of using computers. Sure, OpenCroquet will not help students write papers, etc., but none the less it is a fascinating experiment in what you can do with 3D graphics, in-the-simulated-world "world creation", real time programming, networking, etc., etc. I think that stepping back from immediate practicality and encouraging experiments is a good thing. My young grandson is in the Lego-blocks-experimenting mode; in a year or two I think that he will be ready for OpenCroquet: he is already creative and as he gets older we will upgrade the learning tools that he has.