[Samba] Password from Windows XP

[ofir klinger]

Hello,

I have a network between my Ubuntu computer and my Windows XP computer.
Accessing windows from Linux works fine, but...
when I try to access Linux from windows I get a password prompt.

How do I cancel that password prompt? (I don't want password protection)

Or at least how do I set a password? (Right now I don't know the password)

Regards,
Ofir

P.S
I have Ubuntu 6 with samba 3.0.22 built-in with Ubuntu.