samba - Sep 2000 - a couple questions relating to windows 9x machines connecting to linux

Hi, I've set up samba on my linux machine, and managed to get it shown
on our campus network.
However, I've run into a few problems:
1) I don't know what password it's asking for when I try to connect from
a windows machine.  I suppose it relates to that computer's user name,
but how is this username determined?
2) (relating to #1) I'd like to set a single password for all
connections as Windows does with shared folders.  Is there a way to do
this?
3) When _I_ try to connect to other computers using smbclient, I have to
type in the ip address of the computer in order to connect.  Typing in
just the \\\\computername\\share doesn't work, i have to add -I a.b.c.d
to work...

If you can help me out, please do, thanks.
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Michael Chan
email: mikeyboy@uclink.berkeley.edu