Sorry the scripts for the site are not currently open sourced. The site was developed on a grant from the Japanese ministry of education. It is just the framework you are looking at which I developed. We are hoping to have some more content to put up.
I want to develope a similar tabbed navigation system for moodle but I won't be doing it for the next month or so. I have to make a trip up to Nepal for a few weeks! When I get back I will be developing a site based on moodle and I have more additions planned for moodle which I will also make open source. I'm interested in adding flash based reusable components to moodle.
See also here for more info on what I'm working on :