Zope has a built in FTP server, you just need to turn it on and configure it.

Take a look at your Zope "start" script (pre 2.7) and there is an option for the ftp server IP and port.

So "-f 8021" would put the FTP server started up on port 8021 off of your main IP for the Zope installation.

You can see that the FTP server was started if you are running it in debug mode "-D".

From there, just point your handy dandy FTP client to ipaddress:8021 with a valid Zope username and password which has FTP permissions and you should be good to go.