Joining Samba 3.02rc1 to Active Directory

Hi!

I have currently configured all my linux/unix users authenticate
against an LDAP server. This ldap server is also used for the users in
samba.
I also have an MS Active Directory server on a win2k3 machine running.
The problem I have now is that I want to make Samba a part of the AD
so that the SAMBA takes care of all the user accounts for the win2k3
machine.
(to put it simple -> AD should have no own users (except admin) and
authenticate all the users against the user database stored on the
samba machine)

So, what is the best approach to this problem and how should I
proceed?
I'm not really good with samba nor very custom with AD so any help is
appriciated

Many thanks in advance