sharing file in win2000pro to win98

I intended to try install win2k pro to one of my comp.I am running 5 computer and the other comp. win98 installed. The Quetion I want to pose are :
1. How I managed in win2k pro to share file ?
because if I tried to connect win2k pro from win98 italways ask me for password even the password is correct ?
2. Do you have any suggestion about migrating windows 98 to win2k pro (I am running over 25 comp using TCP/IP peer to peer connection ?