If you are running Windows, Windows Movie Maker is free (sorry, dunno what Mac has). Just use images and/or the built-in slides. You can opt to make people just read while using CC audio, but you will likely see better results if you are sharing something useful and doing it without forcing the viewer to read. Camstasia Studio is great (use it myself) but it costs money and WMM should do what you need for simple vids.
I think Camtasia Studio is probably the most commonly used. If you don't want to pay for software, get linux I did a quick search, and here's an open source one that works for windows. http://camstudio.org/ ---Or you could use a free firefox add on called Capture Fox.
Hello there- I use a free software called Jing. This allows you to capture a screen recording up to 5 min long and either send the video as a live link or download it as an .swf file. Software is good, not squirrely and captures a good screen recording. For FREE, can't beat it. Otherwise, like someone else said, Camsita is really good if you wanna pay.