The Sites page has a few more helpful links, particularly for linear algebra and NMC.
This has a good listing of short linear algebra videos.
This site arose as a result of schools blocking YouTube (So students also wouldn't be able to watch KhanAcademy or PatrickJMT.)
It is like YouTube for learning. The advantage of this is that there are loads of videos together in one place. This is also the disadvantage, as a search can sometimes return too many results.
This is more out of interest; YouTube is better.