In case you don't know, Avant Window Navigator (Awn) is a dock-like bar which sits at the bottom of the screen (or at least it used to, read on!). It has support for launchers, task lists, and third party applets.
The new AWN 0.4 comes with lots of new features, such as:
1. Finally you can position the dock to the left, top or right side of the screen. You can also adjust the distance from the corner. This also works great with multi-screen.
2. New styles:
-Curved:

-Floaty:

-Corner (edgy):

(the element on the left can be any applet you want)
- Extended mode (AWN can be extended to the whole width of the screen). This basically means you can use AWN as a whole gnome panel for instance. Take a look at the following screencast:
Installing Avant Window Navigator 0.4 Beta (0.3.9.1) In Ubuntu Linux
sudo bash -c "echo 'deb http://ppa.launchpad.net/awn-testing/ppa/ubuntu ubuntu_version main' >> /etc/apt/sources.list"
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys BF810CD5
Replace ubuntu_version with jaunty or intrepid.
-For Ubuntu Karmic and Lucid:
sudo add-apt-repository ppa:awn-testing
Then, to install it (for any Ubuntu version):
-If you are upgrading from an older version, do (note: the older version must also be -trunk):
sudo apt-get update && sudo apt-get dist-upgrade
-If you are installing AWN for the first time:
sudo apt-get update && sudo apt-get install avant-window-navigator-trunk
To also install some additional applets:
sudo apt-get install python-awn-trunk python-awn-extras-trunk awn-applets-python-extras-trunk awn-applets-c-extras-trunk
Update: Avant Window Navigator 0.4 final has been released. To install it in Ubuntu Lucid, simply paste this in a terminal:
sudo apt-get install avant-window-navigator
For something similar to AWN, see also Cairo Dock v2.1 and Gnome DO / Docky.
Release notes and image credits: Informatique de Julien