Примерно так
use Net::POP3;
$login = "vasya"; $pwd = "petya";
$pop = Net::POP3->new('pop.mail.ru', Timeout => 60);
if ($pop->login($login, $pwd) > 0) {
my $msgnums = $pop->list;
foreach my $msgnum (keys %$msgnums) {
my $msg = $pop->get($msgnum);
print $msg;
}
$pop->quit;
}