Client Server Network

The company I work with currently has 15 pcs (operating systems – win2k pro, win xp and win 98). we are strongly considering moving to a client server network where the client machines would connect to one server with win2k server installed. I have recommended buying the win2k 25 CAL server OS.

I really want to know the ideal way to implement this network. I have not previously installed win2k server before, and would like to know if I would need to upgrade the machines that run windows 98 when they become clients on the win2k server? I heard that there were some compatibility issues for win 98 clients and win2k server.

Thanks a million