At Montana State University - Bozeman, they use Camtasia Relay for lecture capture and distribution. I wasn't even aware that there was an open source alternative until I saw an "Ask Slashdot" type article where someone asked about lecture capture software... but yes indeed there is the Opencast Community / Projects and the system they have produced, Matterhorn. Check out the embedded video below which is an introduction. As far as I can tell, it (only) offers Flash-based video but I'm relatively new to it and haven't gotten all the details yet. So far as its capabilities and features go, it seems quite impressive.