Once you've set up Windows sharing in Ubuntu, you can start sharing folders. The process is quite similar to what you may have experienced in Windows XP. To share files you actually share a folder.
This is a detailed description about the steps to set up a Ubuntu based server (Ubuntu 5.10 - Breezy Badger) to act as file- and print server for Windows (tm) workstations in small workgroups.
To make a long story short : Samba is a set of tools to share files and printers with computers running Windows. It implements the SMB network protocol, which is the heart of Windows networking.