Your best reference I would think would be the book
Writing Perl Modules for CPAN by
samtregar who is a very fluent and quite well respected contributor to the Perl community. There are a number of reviews of this book available online for browsing - Two such reviews include that in the
January 2003 edition of The Perl Journal and that
on Perl.com.
perl -le "print unpack'N', pack'B32', '00000000000000000000001010101001'"