Rakudo: Revision 1
The Perl 6 Compiler for Parrot is called "rakudo", and it currently lives in the languages/perl6/ directory of the Parrot repository.
To build the perl6 compiler, first get a working copy of Parrot, then change to the languages/perl6/ subdirectory and type "make". This will build the compiler into a file called "perl6.pbc". The ".pbc" stands for "Parrot bytecode", and represents an executable Parrot module.
To run a program with perl6, one then issues a command like
$ parrot perl6.pbc hello.pl
Parrot 0.5.1 does not yet support a #! syntax that allows us to run Perl 6 scripts directly from the command line, but that will hopefully be in the next release - if using recent SVN versions you could use chromatic's instructions to create a parrot executable : http://use.perl.org/~chromatic/journal/35244
For additional build instructions, you might also have a look at this PerlMonks post.