I have found some great online classes, like social anthropology, Math, etc. You can download the lectures, get the book etc. I think that it would be great to organize a study group, by asking who wants to take a course together, and every few days or so check in and have a discussion and compare homeworks, etc.
IT would be great if wrongplanet.net had a section of its site for online group interests and study groups. For taking an online MIT course as I described, a study group should have a blog feature and a chat room. And a person organizer that is responsible for it sends out emails to the group, etc. So each study group maybe should have its own user account?
What do you think of adding a new feature to the website that are online group study/special interest groups?
Have you been to OCW.MIT.EDU? It's awesome. Whole courses listed there. The online course site at MIT even has lecture notes and homework assignments. The Math classes aren't easy and it would be great to have someone to compare/discuss homework with.