[Samba] Samba as user authenticator for Windows systems

[Mobile Assessment Centre]

Hi Everyone:

I am checking to see if there is a way to use Samba as a password server.
specifically, I want the following: when someone who is logged on using
windows 2000/xp/98 and changes their Win2000/xp/98 password, it also changes
the password on Samba/Linux automatically. Any ideas/suggestions?  I think
that if I use the Samba server as a PDC and have the Windows clients login
to the domain, the windows clients will only be able to access the shares
and not their own respective c:drives.  This is what I am trying to avoid.
I would like one password so that when it is changed on the client computer,
it gets automatically changed on the Samba server, and the password allows
access to the client computer's c:drive.  Any suggestions would be greatly
appreciated.  Remember - I am new to this stuff so if my question doesn't
make much sense, please let me know what clarification you need.

Thanks.

Paul