OpenDNS

But what about the children! Won't somebody think of the children?

I'm being silly, but the sad truth is that the 'net can be a pretty slimy place. The best way to watch out for your kids is to monitor and filter their surfing activities. OpenDNS is a simple, effective method of filtering and monitoring the network activity on your home network. Various categories such as games, sports and adult can be easily allowed or disallowed. You can set up a white-list for approved sites, or a black-list for the no-no's.

OpenDNS is not a panacea. A motivated, tech-savvy individual could bypass these restrictions, but for the typical family, it's more than sufficient.

http://opendns.com