Unfortunately I’m not very good at video compositing (I did some video editing for a documentary in the past, but I struggled, didn’t have the right tools nor the know-how).
There are some presentation tools that might be easier to use. In the past I had tried a free tool to create tutorials, but it was Flash based, so it wont’ be any good today.
Today there are some tools to create HTML5 based presentations, leveraging the canvas and other new features of modern browsers. Some of these tools also allow creating a video for YouTube from the presentation once it’s ready, although they are mainly designed for website presentations. So far I’ve only seen commercial tools of this type though, but I’m sure there must be some open source equivalents too (not my field, so wouldn’t know about them).
Still, mixing video captures from the application with voice-over, over-impressing keyboard and mouse clicks, and other similar stuff that makes a tutorial easy to follow, all require some expertise which I don’t have. Other than that, if I can help I’d be glad to.
All of MortMort’s tutorials are really good quality, and you can see him speaking in over impression to the application interface or illustrations, and he also creates nice intros with jingles, special sound FXs, and other cool stuff that show he know what he’s doing.