In theis massive 'build a desktop'-article (51 pages!), LinuxLoader touches upon file sharing in Kubuntu and WMWare.
Here's the filesharing part
File sharing is one of the PCs main reasons for existence. Linux is no different and excels at being a file server (we'll cover that in a Samba Server Build) as well as sharing files between clients. If you have a network like mine, it's a mix of Windows and Linux machines. Say I have completed turning all my Cd's into mp3's and now my wife wants to listen to them on her XP box. We'll cover that. Maybe she has a file that I need on my linux box. We'll cover that also.