Your biggest problem is going to be your usernames and passwords, there are three common solutions to this:
1. Setup seperate usernames and passwords on the 2000 server (I would not recommend doing this but it is the cheapest option)
2. Novellused to have a package called NDS for NT which I believe is now called eDirectory, this will synchronise your usernames and passwords between the two servers allowing you to manage ALL your usernames and passwords in NDS
3. There is another product called Synchonicity for NT which does the same thing as eDirectory
Once this is done all you have to do is setup IPX on the 2000 server (installing the Novell client on the server will do this automatically).
Good luck.