Using KDE, it is very easy to open and edit a remote file using pretty much any application (any application that uses KDE to open files that is). I use this method using Kate (a sophisticated text editing program), and Quanta .
To open a file using ftp, in the box in the middle at the top that shows the current path you are looking at, type:
You will be prompted for a password. After authenticating, you can browse the file system, open, and save the files as if they were local. You may have to re-authenticate every once in a while, but if you choose to save the password, you can click the save password box and use kwallet or a similar password management application.
My favorite way, by far, to work remotely is securely. I value my security across a WAN, so I tend to use SSH if at all possible. This can be done too. Just use the same format, except sftp.
After authenticating, you will be able to use remote file system as if it were your own.
I just ran into a slight problem, mainly opening an FTP connection when the user name has the @ symbol in it, which is common for secondary FTP accounts assigned within CPanel.
To overcome this, instead of using @, use the URL encoded equivelant, or "%40". For example the string ftp://firstname.lastname@example.org@site.com:port/ will not work. You will need to use ftp://email@example.com:port if the FTP user name is firstname.lastname@example.org.