I have written a web based FTP client in PHP, which, on top of the normal FTP functions, also allows you to edit code right from your browser. This is handy if you're behind a firewall at work, or if you're surfing in a cyber cafe.
upload and download files
copy, move and delete directories recursively
chmod and rename
view PHP code with syntax highlighting
Use it and tell me what you think !
PS. Some people have raised questions about the security of their FTP password.
I understand this is the main concern, I would have the same reaction as you do. Remember though that the FTP password is sent in clear text anyway, so your provider, and anyone on the way from your PC to your FTP server can read it...
I am thinking about releasing the code in GPL, then you'll be able to control the code for yourself, or install the application directly on your server.
Anyway, you can test it on a public FTP server (ftp.belnet.be for example, with username "anonymous" and password "firstname.lastname@example.org"). All functionalities will not work because of restricted authorizations -- eg saving an edited document, copying files and directories,...