Ok, this is very straight forward and I will admit, I used the article at http://maketecheasier.com/how-to-install-and-configure-cairo-dock-in-ubuntu-intrepid/2009/01/20 to do this. If you don't know that site, it is an excellent one.
Cairo dock is similar to Avant-Window-Manager (AWN) but does not need any composting
manager (Compiz) to run. I have found, with a little testing, that is uses less CPU than AWN too.
Installation is quite straightforward:
In a terminal:
sudo vi /etc/apt/sources.list
add the following line and save and close
deb http://repository.cairo-dock.org/ubuntu intrepid cairo-dock
add the signed PGP key
wget -q http://repository.cairo-dock.org/ubuntu/cairo-dock.gpg -O- | sudo apt-key add -
Install the application
sudo apt-get update
sudo apt-get install cairo-dock cairo-dock-plug-ins
To Launch the dock
Applications-> System Tools -> Cairo-Dock
To add the dock to startup
System -> Preferences -> Session
Select the Startup tab
When the dialogue opens, click Add
Enter the command cairo-dock in the command to run text box.