A web server probably wouldn't work too bad, depends on what kinds of files you want to share, etc. If you want to share larger files, I suggest that you don't go with http because it's not very good with resuming (incase the person gets diconnected or watever else.) As for ftp servers, depending on what it is that your transfering over your network, your prolly going to far by using an encrypted ftp server.
-Spike