VClass is an open source e-learning platform developed by Distributed Education Center, subunit of Internet Education and Research Laboratory, Asian Institute of Technology. It is specifically designed for delivering on-line courses by two different methods - through "virtual classroom learning" or "virtual class on demand".

In the "virtual classroom setting", there is a synchronous (inter)activity, in which students and instructors participate in live conversations via audio and video while working together with synchronous collaborative software packages for chat or by using VoIP technology.
On the other hand, "virtual class on demand" method allows learners to use computer and communications technologies to work with remote learning resource, i.e., instructors and other learners, without the neccessity of being on-line at the same time.

http://www.vclass.net