Hello, I konw it is not a FW-related software, but sometimes firewalls include some content filtering, and FW users are often interested in content filtering as well. I created a post : https://www.wilderssecurity.com/showthread.php?t=152514 about the free sofware from BlueCoat : http://www.k9webprotection.com/ I think it could be of some interest.
Unless my memory is bad, Zone Alarm Internet Security Suite uses Blue Coat for their parental control.