I am at present evaluating few Open Source LMS(Learning Management System) . The systems I have shortlisted are:

1. .LRN – http://dotlrn.mit.edu/
2. Atutor – http://www.atutor.ca/
3. Bazaar – http://bazaar.athabascau.ca/
4. KEWL – http://kewl.uwc.ac.za
5. Moodle – http://moodle.org/
6. Bodington – http://bodington.org/index.html
7. Eledge – http://eledge.sourceforge.net/
8. Manhattan Virtual Classroom – http://manhattan.sourceforge.net/

These are not in any particular order and will update the list when I finish the evaluation.

Unfortunately there seems to be no mature OSS(Open Source Software) LMS that has a video/audio streaming module built into it. Time to go now and get on with the evaluation.