I use OpenDNS on my home network and the smaller clients that want filtering

Here is a list of default categories you can filter on:
Academic Fraud
Adult Themes
Adware
Alcohol
Auctions
Automotive
Blogs
Business Services
Chat
Classifieds
Dating
Drugs
Ecommerce/Shopping
Educational Institutions
File storage
Financial institutions
Forums/Message boards
Gambling
Games
German Youth Protection
Government
Hate/Discrimination
Health
Humor
Instant messaging
Jobs/Employment
Lingerie/Bikini
Movies
Music
News/Media
Non-profits
Nudity
P2P/File sharing
Parked Domains
Photo sharing
Podcasts
Politics
Pornography
Portals
Proxy/Anonymizer
Radio
Religious
Research/Reference
Search engines
Sexuality
Social networking
Software/Technology
Sports
Tasteless
Television
Tobacco
Travel
Video sharing
Visual search engines
Weapons
Webmail

OpenDNS alog with http://winhelp2002.mvps.org/hosts.htm Works fine on small networks.