There are a couple of free tools that allow you to create video tutorials. Camstudio is one of them, it's a screencasting tool that allows you to record all the video and audio activity on your PC. Jing is another interesting software, just take into account that their videos are limited to 5 minutes. Both are free, so you can try them and see which suits your needs best. Hope I've been helpful.
If you want to do screen recordings you could use quicktime player on a mac. It is free and works great. Thats what I do then I edit it in fcpx. Final cut pro X will give you lots of audio editing options too. If you want to record or change a voice over