In addition to merlyn's advice, although perhaps slightly OT: if you can get your hands on Damian Conway's - Object Oriented Perl you won't regret it. h2xs is just a part of writing a module for CPAN, but much more is covered in the OOP book. And even if you don't write an OOP module, there are loads of neat tips and tricks in there.

Also, take a look at perlnewmod which is included in the docs for Perl 5.6.1

$code or die
$ perldoc perldoc