The Cassiopeia Project is an attempt to produce and distribute high-definition science videos on a range of science topics. They seem more suited for KS4 or A Level teaching. It’s a privately funded project and the videos are available completely free of charge for any educational use. At current count there are over 200 videos available.
As well as being free, the videos can be downloaded, hosted on your own network or VLE and can even be edited to match your own needs. Get students to record their own narrations, add your own subtitles etc. Videos are in Quicktime format.
The videos are available on the Cassiopeia website, and also via iTunes U, so you can download direct from iTunes. If you access them via iTunes U you can also get higher resolution versions, and also access to video transcripts.
It’s an impressive resource, and even better for being free and open for remixing and editing.