Some random things:

%EXPORT_TAGS = (
  Both    => [qw(&lcc_encrypt &lcc_decrypt)],
  Encrypt => [qw(&lcc_encrypt)],
  Decrypt => [qw(&lcc_decrypt)]
);
[download]

Maybe you should change the Both tag into ALL. That's how many other modules export all their public functions. If you add just one other function to the module, you'll have to change the tag, possibly breaking existing code. (Of course, exporting an additionaly function can also break existing code, but still :-).

my $upper = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
my $lower = 'abcdefghijklmnopqrstuvwxyz';

# I didn't do join('' (a..z)) because (in 5.00503)
# it caused errors for some reason.
[download]

I don't see a comma in the join comment. If I do (on Perl 5.00503):

$ perl -e "print join('' (a..z))"

then I get an error, but

perl -e "print join('', (a..z))"

Gives me the expected

abcdefghijklmnopqrstuvwxyz

And for becoming less "wooly" on blessings and objects:

• Object Oriented Perl by TheDamian
• Beginner's OO tutorial
• OO tutorial, part 1
• OO tutorial, part 2 (renamed to perltooc in Perl 5.8.0
• Perl objects
• Perl OO tricks
• Objects hidden behind simple variables

(The perldoc.com search function seems to be broken right now).

Arjen