deb http://ppa.launchpad.net/openoffice-pkgs/ubuntu intrepid main
which I added to my /etc/apt/sources.lst
However I kept getting the NO GPG key authentication error when I was trying
sudo apt-get upgrade
I stumbled onto this GEM. Thanks to lvlo.
gpg --keyserver keyserver.ubuntu.com --recv-keys $KEY
gpg --export --armor $KEY | sudo apt-key add -
$KEY is the value of the package you are not authenticated for.
For Open Office 3.0 I got 60D11217247D1CFF
This worked for me... Hopefully it works for you also.