Then I stumbled on FreeLDAP.org. I think this is the only free LDAP server available on the Internet that could be used by multiple users accessing the same database. The setup instructions on the site do not work with the Mac's Address Book. However, while browsing through their forums, I found this setup which works for me on my 10.4 system.
First you have to signup for a new free account at freeLDAP.org, and remember the username and password. Then, in Address Book, go into Preferences » LDAP and choose New. Enter the following information:
- Name: Freeldap.org (or anything you want)
- Server: ds1.us.freeldap.org
- Search Base: o=entic.net
- Port: 389
- Use SSL: Checked
- Scope: Subtree
- Authentication: uid=username, ou=people, o=entic.net
- Password: whatever you chose for your account
- Auth Type: Simple

