Add Virtualbox PPA for Ubuntu 12.04

Webupd8 posted how to install the latest 12.04 virtualbox PPA (currently it's not on their site).

From Webupd8

To add the VirtualBox repository (which now supports Ubuntu 12.04 too) and install the latest VirtualBox 4.1.12 in Ubuntu, use the commands below:

echo "deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -sc) contrib" | sudo tee /etc/apt/sources.list.d/virtualbox.list
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
sudo apt-get update
sudo apt-get install virtualbox-4.1