Ubuntu One started with an applet back on Ubuntu 9.10 Karmic Koala but it was later removed with the intention of making Ubuntu One as unobstrusive as possible. But that brought a problem: now there is no easy way of knowing the Ubuntu One sync status.
For this reason, Roman has created an Ubuntu One indicator applet which can display the file synchronization status, available space and it can also be used to disconnect Ubuntu One.
In the future, the Ubuntu One indicator applet will support icons to properly reflect disconnected / error state.
Once installed (download the .deb package below), launch the Ubuntu One indicator applet using the following command:
Note: the .deb package below has been built for Maverick so it may not work on Lucid (I can't test it due to some Ubuntu One issues on my computer).
Download the Ubuntu One Indicator Applet .deb | Get the source or file a bug @ Launchpad
Update: UbuntuOne Indicator Applet now has a PPA, works on Ubuntu 10.04!
For more info, see Roman's blog.