How much effort did you really put into searching their site? Just about everything you need to know about it can be found by following the links on this page(at samba.org)
http://us3.samba.org/samba/docs/
In my basic understanding of it, every machine that will act as a data source will need to have a samba server on it, while any machine that needs access to that data will need samba client software on it. With the linux machines, you'll have the ability to mount the shared data across the network as a local filesystem. Windows provides similar functionality through the 'map network drive' process.
It also provides a means of printer sharing also. Good luck in your endeavor.