# pacman -Sy proftpd
Open your rc.conf in an editor:
# nano /etc/rc.conf
And add 'proftpd' to the DAEMONS list.
More to Follow
A more in depth installation & configuration tutorial will come about shortly...
To head off a common problem, for anonymous access to work with /bin/false as the shell for the ftp user (the default configuration), you must add the line "RequireValidShell off" to /etc/proftpd.conf. Otherwise anonymous logins will receive a 530 error.