One of the feature that lots of times ago I was asking to the IE Team was to add an FTP feature to Explorer. Obviously, I've never see something like this on IE.
Now, after the switch to Firefox, I've found the tool I was asking for: fireFTP. This is an FTP client that works like a Firefox plugin and provides easy and intuitive access to FTP servers.
The project is really on an early stage but seems working good... I recommend to try it! 
