How to upgrade from NT4.0 domain to AD and NT4.0 mixed

[Oh]

Hi. My question is: now we are using NT4.0 domain. But now we buy some windows2003 servers and all PC changed to XP. So It's time to upgrade to AD. But because some application can't use in AD, so I want install a windows server 2003 as AD and keep a NT4.0 doman controller (BDC).
How can I do it step by step? Thanks

 

[JimWells]

What application can't use AD?

2003 includes an "Interim" mixed mode that should do what you need. Read up on the different "Functional levels" in Server 2003/Active Directory.