Check the LabAction.com site; it seems to be a real good platform to me. It is basically a Youtube for biology videos. Presently, as the site is new, there aren’t many videos on the site. But if you have videos on Biology lying on your hard disk, do post them.
The only trouble with such sites is that they are heavily community driven, and if the community is not so tech-savvy, not much can be hoped for. The biology community needs to be more tech-savvy than it is at present.