Samba + OpenLDAP PDC: Need some advice

[slurpyx]

Guys.. i've been reading up/researching and figuring out on howto replace my 2k domain controller (which handles authentication and file sharing (Active Directory)) with Linux... in an On and Off Mode as stated on my previous post:

http://tek-tips.com/viewthread.cfm?qid=906755

also.. i am using gentoo as my weapon of choice.. (i kinda like the emerge idea somewhat like a bsd).

Am gonna be implementing 100% Linux Solution for a small group of people.. which will take care of:

-Centralized Authentication (DC)
-File Sharing
-Print Sharing

Anyways, I dig up some documents on Samba and OpenLdap but as a 2K user.. do i have to setup a DNS?

Tnx!