Adding a Windows 2003 Server to an Existing Windows 2000 Server / Terminal Server network.

I will be adding a Windows 2003 server to an existing 2000 server / 2000 terminal server network. The new server will be replacing the 2000 server but the 2000 terminal server will be staying in service.  If I add the new 2003 server to the current domain will it replicate all of the users? If so, after adding the 2003 server to the domain will be automatically become the primary domain controller and be ready to go?  Would i need to demote the current primary domain controller first?  

Thanks for all of your help!