Screencast-O-Matic is one of my very favorite tools for creating video tutorials. Whether you need tutorials for business or for your classroom, this is an extremely powerful tool.
It is free and easy to use, and you do not need any extra equipment to be installed on your computer, as long as you have a working microphone that is built directly into your PC or MAC device.
Sreencast-O-Matic is for use on laptop or desktop rather than mobile. The basic steps to use this tool are:
Click "Start Recording"
Click "Launch" to open the recording panel
Position the recording panel over the part of your computer screen that you want to capture on video
Click record
It will count down, and then you begin talking.
Of course, planning out what you want to say in advance will keep you from having to re-record too many times.
Here's a video tutorial of how to use Screencast-O-Matic created using Screencast-O-Matic.