Unity interface is the default interface in Ubuntu 11.04 Natty Narwhal. It consists of the dock and launchers. However, if you don’t like the dock, animations and the interface as a whole, you can just disable it and login to Ubuntu Classic Desktop.
I just used zsync to download the latest daily build of Ubuntu 11.04 Natty Narwhal. It features Ubuntu Unity Plugin for Compiz among other changes.