I just ran across SciTalks (www.scitalks.com) - a directory of science related videos that are available from on the web. These include such inspiring classics as Richard Feynman's "On the Pleasure of Finding Things Out." Great stuff.
On another note, I've been converting over more of the RCD videos over to WMV so I can post them on the web. I have the remainder of 497 and all of 575. What I can't seem to find is 498. Ill have to dig those up.