Regarding the distribution, Util on #perl6@freenode had started to put together a nice installer for OS X, using Rakudo Star.

His work in progress is here: http://s3.datasaw.com/Rakudo_Star_2011-01_experiment_3.dmg

Regarding multicore, I'd recommend looking at junctions: http://feather.perl6.nl/syn/S09.html#Autothreading_types

Regarding parrot, Perl 6 has many different implementations - The Rakudo team (rakudo is the implementation targeting parrot) works with the parrot team on any blockers or feature requests.