If we could edit online files directly, it would be so convenient because of immediate apply.
Of course, there should be some restrictions by remote IP address or password authentication to cope with security risks, but these may be less troublesome than enabling FTPD on your server.

Web based file management software
This software written in PHP might be useful for you.
Today’s open source software is eXtplorer; an web based file manager.
eXtplorer is written in PHP and has nice interface like as GUI application. You can see the directory listing on the left side. And you will see the content of selected directory.
You can edit any file with specified suffix & change its permission. And all actions can be applied by Ajax on the fly!

On editing
In addition to the normal management mode for local files, eXtplorer can access to external FTP servers.
Adding a new file or directory, renaming or zip/tarball archiving can be done with this software. eXtplorer will be a good partner as long as you want to handle your online files with paying attention to its risk.
eXtplorer – A PHP- and JavaScript- based File Manager
http://extplorer.sourceforge.net/
SourceForge.net: eXtplorer File Manager
http://sourceforge.net/projects/extplorer/
The actions can be applied by Ajax.