use Mail::POP3Client;
  
$pop = new Mail::POP3Client( USER     => "me",
			       PASSWORD => "mypassword",
			       HOST     => "pop3.do.main" );

my $specific_email_subject = "Parse by script";
my $parser_script = "email_parse.pl";

for ($i = 1; $i <= $pop->Count(); $i++) {
  foreach ( $pop->Head($i) ) {
    if (/^Subject:\s+($specific_email_subject)/i) {
      # Special email detected!!!
      # open a 'pipe' to the script that will parse/process 
      # this email message body.
      open(PARSER,">$parser_script |");

      # send email body to the script (will receive
      # it via STDIN
      print PARSER $pop->Body($i);

      # close pipe (end 'transmission')
      close(PARSER);
    }
  }
}