Works great, although I'm not hunting for sites I shouldn't be hunting for, so I can't tell you much! We did some simple tests after we set it up, and my wife and I weren't able to access any porn at all through a google search portal or anything... though it was sure fun trying ;)

You can filter content three ways: by category, and by IP, and by Domain Name. There are like, 30 or 40 categories, and you just check the box to filter that category. You can filter out image searches (like google image and fotosearch.com) and best of all, you can filter out ads!!!! It will block ad banners from showing on facebook and myspace if they are served from IPs that are filtered out. So say goodbye to all those dating ads on myspace! They mostly come from porn sites, in case you didn't know.

You can then allow certain sites on a whitelist. So, we blocked social networking sites, then allowed facebook, so none can access myspace or a less desirable social networking site.

It's a very good system.

Blessings,
Tony

We've been using OpenDNS for a while and it works great! Highly recommended!

Been using it for awhile now myself. I'm very happy with it. Have it set up through my router so the whole household network is on it. Even when browsing via wifi on my iphone.
also as anthonypero stated, were not looking for the bad stuff anyway.

I went ahead and set it up on my desktop over top my other filter. I like it pretty well so far.

I use OpenDNS.com and it is a good start to web filtering.
However it is a DNS only filter, so if the DNS record is not in the database, it doesn't matter how bad the site is, you'll still be able to load it.
I have since layered this with an untangle firewall with webfilter. http://www.untangle.com
It's easy to use (Assuming you have a spare box) and makes a great second layer to web filtering.
It's a little over the top for a home install (I have 2 teenage boys) but works wonders at work.
I installed my home firewall on a refurbished HP SFF desktop that I picked up for under $100.

I've been using openDNS for about 2 years now and am very happy with it. The free version has limited reporting but it get's the job done as far as blocking most sites. Like other's mentioned it's not completely fool proof since it just uses DNS to do the blocking. But for most Churches it should be enough. The paid version provides CIPA compliance which may be important for some schools. Overall I'm very happy with it. Like all the rest I'm not pushing the limits by searching for inappropriate content but it does block sites associate with spam, viruses, malware etc. Which can help keep machines running smoothly longer.