Here’s the instructions straight from Microsoft how to <a href=”http://support.microsoft.com/kb/814591″>setup DNS on Windows 2003</a>.
Since it’s AD-Integrated, the server would become automatically an active DNS server not just a secondary backup. Once this is setup, just configure your DHCP Server to provide this additional DNS server.
Note: Only DNS servers that run on domain controllers can load Active Directory–integrated zones.
In other words, the easiest way is to install DNS on another server, and make it a domain controller.