I used OneButton FTP, Secure FTP looks like a better program. You can also use finder as a FTP Clint I will decribe how to...
I don't think you need to start FTP access in the system preferences. From the desk top hold down the command key (the one with the apple on it) and press <k> or goto the Go menu and select connect to server. With that open you now type ftp://YourServer.com and then it mounts and looks like your HD. I think that's it