Generally when introducing a Win2000 server to an NT domain as a DC you have to do it as an upgrade to the existing PDC. Win2K WILL act as a PDC for an NT 4.0 domain (It will default to mixed-mode operation), but the only way to do it is to follow the upgrade path- once you upgrade the PDC to Win2K the ohter BDC's in the domain will treat it like a PDC and any Active Directory clients (IE other W2K servers and W2K professional systems) will treat it as the AD server.
Question- are you buying this machine pre-installed with 2000? If not, what you could do is first do a stripped down install of NT4 as a BDC, promote it to PDC, remove the old PDC from the network, then do the 2000 upgrade.
As noted previously, this is NOT a trivial undertaking. Research thoroughly before you proceed.