Authentication with Windows

I have a Windows 2003 server running DHCP, DNS and acting as a Domain Controller. I have Active Directory running for windows users and Group Policy to enforce certain rules. I will like to get Mac users to authenticate to this server and if posible to be able to restrict the machines using something like GP in windows environment. Is this possible??? If yes can someone guide me through this, since I am a newbie in the mac world.

Thank you

http://images.apple.com/macosx/pdf/MacOSX_Windows_TB.pdf

http://docs.info.apple.com/article.html?path=DirectoryAccess/1.8/en/c7od44.html
http://docs.info.apple.com/article.html?path=DirectoryAccess/1.8/en/c7od45.html