References
I have used the below books to design our Active Directory Group Policies - we use GP's for quite a bit (deploying software and to enhance security).
Group Policy, Profiles, and IntelliMirror for Windows 2003, Windows 2000 and Windows XP by Jeremy Moskowitz
Windows 2000: Group Policy, Profiles, and IntelliMirror (The Mark Minasi Windows 2000 Series) by Jeremy Moskowitz

Old ADM files
Download the most current, or any previous version of Group Polciy ADM files.  Microsoft's Download Center has a page where you can download ANY version of a set of ADM files since their release (thanks, Jeremy Moskowitz of http://www.GPanswers.com)
http://www.microsoft.com/downloads/details.aspx?FamilyID=92759D4B-7112-4B6C-AD4A-BBF3802A5C9B&displaylang=en