So, if you have an Active Directory and your using SMB authentication to Windows, this is pretty simple. In Applications -> Utilities -> Directory Access is a list of Directory Services that you can enable for Authentication methods on your Mac OS X systems. You can set up your OS X machines to authenticate against your existing AD, if you like, rather than your local accounts, for better security. Also, this will enable Kerberos, so that the users do not have to authenticate for their SMB shares on the Windows server, they simply can connect to it, like any other Windows client could.
Take a look at the plug in and let me know if you have any questions!
I have a link to my website in my sig. If you click on the Connect link, it'll email me from there, if you need really specific instructions for your domain.