Check out:
http://www.allfacebook.com/2009/02/facebook-privacy/ for a good introduction to some of the most critical privacy settings
in Facebook. With social media sites being used by more people to
manage personal as well as business contacts, everyone needs to know
just how much of your privacy is protected when using Facebook and
similar sites. Most social networking sites have default settings
designed to encourage sharing of information and contacts, leaving your
privacy at risk. This article represents a good starting point for
learning about how to change the default privacy settings in Facebook to
better protect what you share, and who you share it with. Share and
Enjoy.