Network a Mac and PC HELP

Hi, I need to set up my clients mac to where when he drops file in a folder on his mac it was transfer them to the PC, would it be easier to get a transfer cable (USB or Firewire) or would is there a way to network the two different computers (mac and pc) with shared folders?

If you connect a Mac (OS-X 3.9 or later - maybe some earlier, but I know for sure 3.9 or later) to an existing PC workgroup network with shared folders, the Mac will automagically (or nearly so) "find" the PC network's shares and attach to them.

Also, as Blue said, USB drives can be easily shared between Macs and PCs.

I have no experience with PCs having access to folders on the Mac. But the Mac accessing folders on the PCs is easier than another PC accessing them.