samba - Feb 2007 - Newbie question, authentication with UNIX accounts, not smbusers/smbpasswd

Hi all,
I would like to access my RedHat Enterprise box which has Samba 3.0.9, 
by mapping a network drive from WinXP and specifying the UNIX 
account/password on the server. Is this possible? I can duplicate 
account usernames/passwords into smbusers/smbpasswd, but doing this for 
every user is a pain.
Thanks in advance for any suggestions or pointers,
Phil