use MIME::Entity;
use Mail::Mailer qw(sendmail); 

my $email = MIME::Entity->build(Type       => "multipart/alternative",
                             To         => 'somebody@example.com',
                             subject    => "Test Email");

$email->attach(Data        => ["THIS IS DIRECTLY ATTACHED TEXT"],
               Type        => "text/plain; charset=UTF-8",
               Encoding    => "quoted-printable");

$email->attach(Data        => ["<h2>THIS IS HTML TEXT<h2>"],
               Type        => "text/html; charset=UTF-8",
               Encoding    => "quoted-printable");

$email->print(\*STDOUT);
$email->send;