While searching for videos on the use of a hemocytometer, I happened upon the Journal of Visualised Experiments. Go on… have a look.

They also have a sister site here:
dnatube.com

It’s a blog/youtube site for Science only, and has some decent videos sorted into categories. I’m still trying to work out how to save or embed these videos, but it’s well worth a look. Great for introducing up-to-date Science topics in class.