Internet monitor/filter solution for home network

You should be able to easily go into your router settings and set it up so that OpenDNS is the default dns server and all machines which connect through your router will get that by default. I say by default, as a different DNS can easily be set on each machine individually.

Just remember to often check your ip address to see if it changed or not, and if it has, to log into opendns and update your mapping. Most broadband ISP's will continue to serve the same IP address for a very long time, but any outage can easily cause the ip address to change and this just might cause your OpenDNS filters to fail.

The other methods of restricting traffic (proxy servers, for instance) would require additional hardware and management and I personally wouldn't recommend them for home use. There is a way around just about every system, so in the end its going to come down to your home network policy. Place the roadblocks to stop the "accidental" stumbling, and then make sure that all users know the risk of "going around" them. In my household its a mac address block on that machine which disables the network (this works good for the gaming consoles too).

I've had great success at home with an old box, 2 nics and the free version of Untangle. Untangle is the "appliance" and helps manage and report on just about everything I need to worry about with 3 kids from 9 - 17.

I have it configured to use OpenDNS and, in an admittedly belt and suspenders fashion, also use OpenDNS for filtering as well.