To run an FTP server you need software...
I reccommend
BulletProof
FTP Server, but you can find other free software out
there. Any FTP serving software will do... just make sure
to follow the instructions carefully, ESPECIALLY of you
are behind a firewall!! Another good thing to have if you
decide to run an ftp server is
DynDNS...
it gives you a free hostname (Ex: you.dyndns.org) which
updates automatically to your new ip address every time
it changes (like when your connection resets).