on what are you going to host the FTP on, your PC at home? I believe Filezilla will do the job and its free, only thing you need to do ideally is set you home pc with a static ip and port forward port 21 to the IP of your pc, then when someone connects to your internet IP (i use
www.whatismyip.com) with the FTP command and then uses the username/password you supply them
The programs help is very good, but post back here or msn me and i'll help you out
Andy