WatchKnow is open and collaborative project to collect and organize educational videos related to educational purposes. I use YouTube a great deal but then my students are graduate level. K-12 teachers have a real concern turning their students lose on YouTube or on the world-wild-web. I like what I've seen browsing WatchKnow and I like even better the idea that solution to the side-effects of the Internet is to use the "wisdom of the crowds" to organize content into sites that serve a specific function.
WatchKnow is in beta and is well worth watching. I wish them luck.