Avant Window Navigator (Awn) is a dock-like bar which sits at the bottom of the screen. It has support for launchers, task lists, and third party applets.
Update 25/10/12: Awn is not available in Quantal (12.10).
Open a terminal window and run the command below. It'll install Awn and all its applets.
sudo apt-get install avant-window-navigator awn-applets-all -y
Awn can be accessed via Applications Menu > Accessories > Avant Window Navigator or typing the following command:
Awn settings (size, position, autohide, applets, ...) can be customized; right-click on Awn and select Dock Settings.