Add a W2K Adv Svr to an NT4 Network

Hi all. I need to add one Windows 2000 Adv Server to an existing NT4 network. I need it to leave my existing domain alone and just be another server on the network. Yes, I have already determined that I need it. However, should I add it as a seperate Domain on the network so that I can switch it to native mode? Do the trusts of NT work with the trusts of Win2K? What are my pitfalls in having one NT4 domain and one Win2K domain?