Libreoffice is now available and installed easily for Ubuntu 10.10 and 10.04 by adding the libreoffice ppa.
The following steps allow the addition of the ppa and the installation of LibreOffice:
Optionally OpenOffice can be removed with the command
sudo apt-get purge "openoffice*.*"
on the commandline.
The LibreOffice ppa can be added on Ubuntu 10.10 and 10.04 with
sudo add-apt-repository ppa:libreoffice/ppa
sudo apt-get update
Libreoffice can then be installed with
sudo apt-get install libreoffice
Depending on the Desktop that is (Gnome or KDE), the following command is necessary:
sudo apt-get install libreoffice-kde
sudo apt-get install libreoffice-gnome