Peer-to-peer ort ftp file sharing over internet?

Help,

I'm trying to find a way to use OS X's ftp capabilities to share large files with family over the internet, but am running into problems.

Does anyone know a relatively easy way to set up the ftp functionality of OS X or how to get it to work? I'm trying to make my computer accessible as an ftp server, but my dad can't seem to log on using my account name, password, etc. Is this really possible? Theoretically can I just turn on the ftp client in OSX and allow other users on the internet to log in and swap files? If this wouldn't work, what else could I use aside from having to buy server space online to swap the files.

any help muchly appreciated,
max