The Rakudo Perl 6 Compiler ("rakudo" for short) targets the Parrot Virtual Machine, and it currently lives on github. Its developed by Patrick Michaud (pmichaud - lead developer), Jonathan Worthington (jnthn), Stephen Weeks and others, mostly using NQP. It will most likely become the "official" Perl 6.0 release.

To build the Rakudo Perl 6 compiler, follow the instructions on the official homepage.
Parrot and Rakudo change rapidly; if you have issues with the latest point release, be sure to try svn/git-latest of parrot/rakudo.

Also check out Getting Involved to learn about how to help with development, and see A Guide to the Pugs Repository for Rakudo Hackers.