ive gone through several tutorials and everything seems to be configured properly, my vista pc sees my Ibook, but when i click on my ibook in the network window it asks me for username and password, which i would assume would be my login information for my ibook, but when i enter that, it says its invalid, so my question is how do i determine exactly what it wants as login information. Ive tried all logical possibilities. thanks in advance.

Use the login pass for the computer you are trying to get to. After all, that is the computer you are accessing so it makes sense to use the login for it.

I have the same issue with Ubuntu. I try to log into Ubuntu from my windows network and it asks for a user name and password. I enter the username and password for the Ubuntu computer but it doesn't connect. I can access the windows computers and a Mac on the network from the Ubuntu computer. I am missing something in the network setup, or users and groups. I don't have an answer as yet but will keep you posted.
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Did you create a Samba user on the Ubuntu machine with the same name as the Linux user? Something like "smbpasswd -a username" and "snbpasswd username"

When logging in from the Windows computer, you may have to give the Linux machine name as the login "domain". Sth like UBUNTUHOST\username

Try just a normal user id / passwd identical on both systems.
I find that when my Linux is running AND the same user-id active on both, Samba connects easily.