Exchange Migration

I am going to be migrating from an NT4 server running Exchange 5.5 to a 2000 DC running Exchange 2000. Does anyone out there have a few tips as far as what to look out for and any potential problems that may arise? I have been reading a lot on TechNet. Are there any particular articles on TechNet or elsewhere that would be good to read before I do this?
Thanks in advance for your assistance.