Samba 4 is finally into the betas. This new distribution offers AD management of PC's for free. Can not join existing domains, yet. (2012-06) - http://www.resara.org/index.php/features
A set of instructions to create a domain for Windows workstations with open source software. Use OpenLDAP and Samba. Does not do group policy - I think - http://ubuntuforums.org/showthread.php?t=640760
Another Samba + AD tutorial: http://www.golinuxhub.com/2014/02/how-to-configure-samba-4-secondary.html
Interesting, a little shim that will logon to network shares. Attempts to bring benefits of centralized data (file) permissions to users on XP Home in small office situations. Might be good for home use too. Maybe not. Open source.
http://www.mylogon.net/
tags: AD, XP, server, networking, network, logins