is there a way to discover if a particular module is included in the core?

Have a look at perldoc perltoc under 'PRAGMA DOCUMENTATION' and 'MODULE DOCUMENTATION'. Online you can find it here for perl 5.8.0 and perl 5.6.x.

For additionally installed modules you can try perldoc perllocal. And to simply see if a module is installed use perl -MModule::Name -e1.

And as a side note ... you can edit most of your posts here on the monastery (apart from certain root nodes), so there's seldom a need for a repost.

-- Hofmator