I have set up a Mac as a server using the network preferences. I assigned the Mac an IP address of 10.0.0.1 and then set it to connect using FireWire.
Then, I enable all the sharing settings in the preference pane, and enable Internet sharing (make sure to enable FTP access).
Then, I disable the firewall.
At that point, I can then connect the firewire cable between my PC and the Mac, and have the PC automatically detect the connection.
I set up the PC with an IP address of 10.0.0.2 on that network connection (ethernet over firewire).
I also set up the network gateway on both machines as 255.255.255.0
At that point, I can use any FTP program on the PC to log onto the Mac and browse it's hard drive (and even disk images and CD's / DVD's).
You must configure the FTP program to FTP to the Mac's assigned IP address, and then provide it with the username and password you use on your Mac. This would be your regular administrator username and password.
It takes some tinkering, but once you get it setup, it works great.
I also setup this particular configuration as a separate "Location" in OS X. This way I can toggle between server and regular DSL modes without much effort.
You will want to be sure to disable all the sharing options and re-enable the firewall when you are done. This will make sure your systems protected again.
I've used this method to transfer files to and from my Mac many times. It works great. Especially for 2 and 3 gigabyte files (DVD projects).