Can I connect to Ubuntu One via FTP?

The best way to get all your files is to just install the Ubuntu One client as normal.

However, if you're unable to do that for some reason, you can use u1ftp as a stopgap. Download from Launchpad; u1ftp is explained by James Henstridge here and there are some demonstration screencasts and descriptions here. It works on pretty much every desktop platform (Ubuntu, Mac, Windows, Fedora, Suse, etc), and it makes Ubuntu One available over FTP to the computer you're on, so you can access U1 directly as a network drive in Nautilus or Windows Explorer or Coda or by mounting it as a drive, and it connects securely to Ubuntu One via the U1 files API and SSL.

Ubuntu One does not provide an FTP service. If you need all the files the best way to do it is just to use the regular ubuntu one client and setup your account.

Just a suggestion look at this, however if you need a local backup use unison.