All Mac Network to add single XP box to LAN

One of our clients is requesting that we get an XP box and install Project 2003 so we can update their Project server with our project files. So I’ve got this box all setup, no SP2, but took NSA setup guides. My users will access the machine from their Macs using VNC but now I am looking into how I’ll allow my users to transfer files to and fro their Macs and this single PC. Do I add Win sharing to my AFP box, or simply set up folder sharing on the PC and let the Macs connect to it?

Thanks for any thoughts,
d