The libreoffice team have not updated their PPA with any newer version of libreoffice beyond 3.3.2 for maverick and natty. I note (at the time of writing this) they have attempted to produce a build of 3.4.1 for Oneiric.
Reading the oneiric blueprint - the libreoffice will be updated for lucid/maverick/natty when oneiric has been successfully tested/built. This will either be through the PPA or through the standard backports repository.
Whilst we wait - see this AU Question as a guide on how to update to the latest version of Libreoffice.