Screencast Addiction

Ruby/RoR
http://www.railsenvy.com/speaking
http://railscasts.com
http://www.rubyplus.org
http://www.buildingwebapps.com/podcasts
http://peepcode.com
http://www.pragprog.com/screencasts
http://envycasts.com

Rails Conf(s)
http://www.railsenvy.com/tags/conferences
http://www.railsenvy.com/2008/6/2/Railsconf-videos
http://blip.tv/search?q=rails+conf&x=0&y=0
http://www.confreaks.com
http://mwrc2008.confreaks.com/
The RubyFringe Videos

OSCON
http://www.railsenvy.com/2008/7/29/oscon-videos
http://blip.tv/search?q=oscon&x=0&y=0

Other
ThoughtWorks IT Matters and ThoughtWorks Talks
http://www.justin.tv/signals37/archive
http://developer.yahoo.com/yui/theater/
http://www.theflexshow.com/blog/
Gooogle search railsconf
Google search oscon
InfoQ Presentations