You could use Samba 3.0 to setup a Windows NT like domain, but Linux doesn’t have anything comparable to Active Directory at this point. There is a thesis that has been written about using Samba 4 (the version under development) as an Active Directory DC, but since it’s not out yet, you’re out of luck there. I don’t know of any other works that have been completed that allow a Linux machine to talk to the Windows environment, but there may be others. Samba has probably come the closest to doing it and is by far the most popular.
The thesis mentioned is located here: http://samba.org/samba/news/articles/abartlet_thesis.pdf
The Samba site is: http://us2.samba.org/samba/
Mandriva/Mandrake has samba RPMs that you can install. You can either use Webmin or edit the configuration files manually to configure it. Mandriva also has RPMs for installing webmin.
Hope this helps,