In case you're interested, there's an Active Directory integration test day for Fedora 18. Testing stuff like sssd and realmd with Active Directory.
http://fedoraproject.org/wiki/Test_Day:2012-10-18_Active_Directory
I'll be trying to get an Active Directory domain setup. But if you want to setup your own domain ahead of the test day (it's not that hard) then you can do so like this:
http://stef.thewalter.net/2012/08/how-to-create-active-directory-domain.html
See you there ;)
Stef