One of the best things about Synergy is that it is cross platform and works with Linux, Windows and OSX. The easiest way to use Synergy on Ubuntu is to install QuickSynergy which provides a GUI for managing screens and connections.
|The QuickSynergy UI on Ubuntu 10.10|
There are two ways to install QuickSynergy, either open the Ubuntu Software Center and search for "synergy" or type the following at the terminal:
sudo apt-get install quicksynergy
The QuickSynergy icon will now appear in your "Accessories" menu.
I have also written up a guide to installing QuickSynergy in Meego: