Python3 installed under jaunty for me just now without a hitch. So at least if the upgrade from Intrepid to Jaunty has been completed then Python3 is available / installable thereafter under jaunty.
As I recall, my upgrade from intrepid to jaunty also entailed problems with the installation of python 2.6 being in conflict with the then standard use of python 2.5. That problem got corrected in the course of jaunty being upgraded daily (my common practice).
Python3 installed under jaunty for me just now without a hitch. So at least if the upgrade from Intrepid to Jaunty has been completed then Python3 is available / installable thereafter under jaunty.
As I recall, my upgrade from intrepid to jaunty also entailed problems with the installation of python 2.6 being in conflict with the then standard use of python 2.5. That problem got corrected in the course of jaunty being upgraded daily (my common practice).