debian package

git clone https://github.com/dotcloud/docker
cd docker
git checkout packaging
make deb
cd ..
sudo dpkg -i docker-dev_1_amd64.deb

# You might need to install dependencies with
sudo apt-get install -f

Once launchpad is up, add to /etc/apt/sources.list

deb http://ppa.launchpad.net/noise+ppa/docker-dev/ubuntu precise main