http://www.sorensonmedia.com/video-delivery-network/
http://www.sonicfoundry.com/mediasite
http://www.tegrity.com/
http://echo360.com/
http://www.ustream.tv/
http://new.livestream.com/home
http://youtube.com
http://www.brightcove.com/en/solutions

Encoders
http://www.telestream.net/pipeline/features.htm
http://www.ncast.com/
http://www.polycom.com/products/uc_infrastructure/realpresence_platform/video_content_management_solutions/enterprise_video_capture/realpresence_capture_station.html
http://www.vbrick.com/products/capture/video-encoder.asp
http://www.myvulkano.com/products.html
http://www.digital-rapids.com/products/individualproducts/touchstream.aspx
http://www.haivision.com/products/makito

All of these can be integrated into some form of lecture recording and capture.