Just to make sure you are forewarned, if you try to use Samba as a PDC for Win2k boxes with sp2, you might run into problems. When sp2 was released, things were apperently changed enough to prevent joining a Samba 2.2.0 controled domain.
To get around this, you could download the current Samba 2.2 development code via CVS and compile it yourself. I have gotten Samba 2.2 (running on FreeBSD) working as a PDC for Win2k sp2 boxes this way.
Because you are new to Linux, and also because you might not like using development code, you could just wait until 2.2.1 is released with the sp2 compatibility fixes.
However, If you don't have any intention of using Samba as a PDC, then please ignore everything that I have just written.