You might find this useful. Kanji gave me this little sample snippet that he wrote:

package My::Debug;

use base Exporter;
use Data::Dumper 'Dumper';

our $DEBUG_LEVEL = 0;
our @EXPORT      = qw( debug debug_level );

sub debug
{
    return unless $DEBUG_LEVEL;

    my($pre_msg,
       $var,
       $post_msg) = @_;

    no warnings;

    print join( "\n", 
      "",
      $pre_msg,
      "<" x 20,
      Dumper($var),
      ">" x 20,
      $post_msg,
      ""
    );
}

sub debug_level
{
    $DEBUG_LEVEL = shift;
}

1;
[download]

Elsewhere...

use My::Debug;

debug_level( $opt_v );

sub foo_sub
{
    ... code ...
    debug('begin showing foovar', $foovar, 'end of foovar');
    ... code ...
}
[download]