Confira OpenDNS . Do site deles, a ênfase é minha ...
Setting up OpenDNS parental controls is as easy as making one simple change to your wireless router. Follow our detailed instructions for your wireless router's settings, then choose the content you want to block. OpenDNS takes effect across your entire household immediately – from your family computer to your kids' gaming console. Because OpenDNS Internet parental controls also provide you insight into which websites are being visited on your home network, the service allows you to easily discover new problem websites. If you see an inappropriate website appear in your account statistics you can quickly and easily block the site and, if you wish, the category of content to which that site belongs.
E é grátis:)