OpenDNS offers a FREE solution for families to filter websites that most parents do not want their children to find or visit. No account required, you just point each computer or your router/wireless device the DNS addresses to the OpenDNS servers listed below and their default filters block content.
208.67.222.123
Alternate DNS server address for Open DNS is:
208.67.220.123
OpenDNS FamilyShield website
For a more configurable web filter, OpenDNS offers another free solution where you create an account and customize the web filter as well as get reports for the past week.
You can also pay for an upgrade and get more features.