Launchctl allows Mac users to load, unload daemons/agents and generally control launchd. To load the FTP server, just run the Terminal app and run the command:
sudo -s launchctl load -w /System/Library/LaunchDaemons/ftp.plist
And just like that FTP is now enabled.
You can unload the FTP server by also using the launchctl command. To unload the FTP server, just perform the following command in the Terminal app:
sudo -s launchctl unload -w /System/Library/LaunchDaemons/ftp.plist
For WordPress developers, the FTP server is a convenient software when upgrading WordPress and plugins running on the Mac.
[Update: 19-Nov-2013]
Accessing the FTP server
After setting up the FTP server, you can access to it using the web browser. You can also use an ftp client like Forklift for the OS X or Filezilla (runs on both Windows and OS X).
Using your Mac’s OS X username and password, you can gain access via localhost (for ftp access from the same computer). To access the ftp server from another computer over your network, useyour computer’s IP address.
For example, to access the FTP server using a browser, just use the following URL format:
ftp://user@localhost (you will then be prompted by the password)
via: http://igerry.com/desktop/apple-os/enabling-ftp-server-os-x-mavericks.html