In 
a previous post I summarized a paper using two programs: 
Prezi and 
Screencast-o-matic.  Both are free and easy to use.  The screencast above shows how I did it. Anyone can do this.
I did this on a mac, so I used the earphones/microphone that came with my iPhone.  The sound is not the greatest, but good enough I think.
The screencast is 9 minutes long, which might be too long.  It's hard to strike a balance between detail and the big picture.  Hopefully, I will improve with time.  Feedback is very welcome.