Kidoz is a free desktop application that acts like a safe content management system and turns one's computer safe for their kids. There are a bunch of features to like here such as filtering the internet for kids, allowing safe links and videos to pass through. Also, there are parental controls that can be adjusted as well as safe email for kids.
I highly recommend checking out Kidoz by clicking here!!
For another similar free application I recommend checking out Bumper Car.