* Debian-based Linux distributions: Add one of the following lines according to your distribution to your /etc/apt/sources.list:
deb http://www.virtualbox.org/debian gutsy non-free
deb http://www.virtualbox.org/debian feisty non-free
deb http://www.virtualbox.org/debian edgy non-free
deb http://www.virtualbox.org/debian dapper non-free
deb http://www.virtualbox.org/debian etch non-free
deb http://www.virtualbox.org/debian sarge non-free
deb http://www.virtualbox.org/debian xandros4.0-xn non-free
The innotek public key for apt-secure can be downloaded here. You can add this key with
apt-key add innotek.asc