Hi, it will not use the internet, this will be simply computer to computer.
If you go into control panel you should see a networking and file sharing or something similar if on xp. There you can setup file sharing.
If you then go into system, you can change the workgroup name, should by default be the same.
Then you should have a shared folder, if not then right click the folder you want to share and click the sharing tab and allow it there.