Here's David Friedman on anarcho-capitalism, embedded at Let A Thousand Nations Bloom. You can get, among other things, the first edition of his classic The Machinery of Freedom at his website. This would, of course, make an excellent companion for a reading group studying For a New Liberty.

Addendum: Here's Friedman arguing that we should get rid of criminal law. It's great background for data entry on the history of legal systems.