http://sial.org/howto/perl/life-with-cpan/
####
sudo perl -MCPAN -eshell
cpan> o conf make /usr/bin/make
cpan> o conf commit
##
##
cpan> install Getop::Long
---snip---
/usr/bin/make test -- OK
Running make install
Manifying blib/man3/Getopt::Long.3pm
Installing /System/Library/Perl/5.8.8/newgetopt.pl
Installing /System/Library/Perl/5.8.8/Getopt/Long.pm
Installing /usr/share/man/man3/Getopt::Long.3pm
Writing /System/Library/Perl/5.8.8/darwin-thread-multi-2level/auto/Getopt/Long/.packlist
Appending installation info to /System/Library/Perl/5.8.8/darwin-thread-multi-2level/perllocal.pod
/usr/bin/make install -- OK