There are a couple options for getting more info.
From the command line you can get the number of items in the queue with these commands run in the terminal:
u1sdtool --waiting-metadata | wc -l
you can track progress as the numbers get smaller. It syncs metadata first (folder structure) then content. You can remove the '| wc -l' from the command to get more details about the items in the queue.
u1sdtool --waiting-content | wc -l
NOTE: In Natty(11.04) and Oneiric(11.10) these commands have been combined into one command.
A good wiki page that provides information on using u1sdtool to get more info from Ubuntu One.
u1sdtool --waiting | wc -l
Ubuntu One Client Control
There is also a project called Magicicada that is a GUI for the Ubuntu One syncdaemon. It allows you to connect/disconnect and see the items in the queue. You can install it with these commands in a terminal:
For Lucid you will have to add the ppa. If you are on maverick and newer the package is in the repository and you can skip to the next command.
sudo add-apt-repository ppa:chicharreros/ppa
You can launch the application from Applications > Accessories > Magicicada
sudo apt-get update; sudo apt-get install magicicada
Lastly there is a project that brings back the indicator some may remember from early versions of Ubuntu One. You can install it with these commands run in the terminal:
add the ppa
sudo add-apt-repository ppa:rye/ubuntuone-extras
to run the app issue this command
sudo apt-get update; sudo apt-get install ubuntuone-indicator
You can add this command to System > Preferences > Startup Applications.