A lot of people try to have a perfect integration with  Windows Active Directory and a Linux Box. If you try it by yourself with editing the samba files and some basic GUI you will have an hard time and a headache in a lot of Distro.

If you want to simplify your life go with Centrify Express:
http://www.centrify.com/
http://www.centrify.com/express/free-active-directory-tools-for-linux-mac.asp?r=menu-nav

This software is really easy to install and fit with *all* the distro. Just follow the 3 pages install guide.

They have a Samba “server” module to share some folders from your linux box to users in the Active Directory. This package is a bit more difficult to setup but follow the guide and everything work great. If you set this up correctly the Windows Users will not be prompt for credential, the linux will check the Active Directory to authenticate the users !