Anyhow, the Plank dock is created by the Docky Core Team thus it inherits a bit of this and that from docky as well. It is written using a new programming language called Vala (created by Gnome developers) which has a reputation of being able to create software that use less memory requirements.
Although you won't get a lot of features with Plank but you can add/remove apps or shortcuts and make it automatically hide when not needed, etc nonetheless. Once installed you should be able to access it via: Applications -> Accessories -> Dock Plank.
In Ubuntu 10.10 and 11.04 you can install Plank by issuing the below command.
sudo apt-add-repository ppa:ricotz/docky
sudo apt-get update
sudo apt-get install plank