It is not hard, although the first time it might appear to be overwhelming.
You will need to post the system that you are using. I presume it is Ubuntu.
You will need to work on you own Samba file. Make a copy of it for reference purposes. (I use openSUSE. My file is smb.conf)
The Windows boxes will each need to have a user name, and a password. They will need to be the same in you Linux box.
They will all need to be part of the same network.
You will probably need static addresses.
You will need to set up your Host Names, or something similar.
You will probably need to add each of the users of the other computers to your Linux box (add to Users). Then they can access their own user space on the Linux box.
You will need to use a terminal in root to allow the users to access the Samba shares. (smbpasswd -a <username>)
You will have to open the ports in the Firewall.
If you have them access any other part of the Hard Drive on the Linux box, you will need to deal with permissions.
Last edited by davesny; 11-09-2011 at 04:25 PM.