Screencasts are now the most used resource on internet for showing someone how to do something on the computer. Professional developers are now showing how to program, create content for web, graphic applications, etc. , motivated by paying back to the internet community.
I have started the series of screencasts on the C programming language, I start though, with studying skills for programmers and gradually advance towards more advanced subjects.
I'll keep you updated, as soon as new videos are finished.