Picard 0.13 was recently released and thanks to the packaging efforts of Michael Wiencek we now have a working Mac DMG for Intel Macs running OS X 10.4+! At this point we do not have any support for older PPC Macs and it doesn’t look like we will ever have support for that. Sorry. There is an older 0.11 Universal Binary that PPC users can use.
Thanks to Lukáš, Philip, Michael and everyone else who worked on this release!
UPDATE: You see a change log for this release here.