Add the following line in /etc/apt/sources.list file:
deb http://backports.debian.org/debian-backports squeeze-backports mainAfter adding this, perform an update and install the package libreoffice from the squeeze-backports suite using the package management software of your choice
(e.g. apt-get update ; apt-get install -tsqueeze-backports libreoffice).Previously installed OpenOffice.org packages should be uninstalled automatically. Depending on the used desktop environment, you might also have to install the libeoffice-gtk, libreoffice-gnome or libreoffice-kde packages.