This directory contains experimental up to date libguestfs packages for Ubuntu 12.10. You should be able to install them by adding this line to
deb http://libguestfs.org/download/binaries/ubuntu1210-packages/ /
You will need to also:
sudo chmod 0644 /boot/vmlinuz-*
because of this Ubuntu bug.
Let me know if the packages work. Also what other versions of Ubuntu I should be building them for.