YES! I GOT IT! Wow -- thank you so much everyone. Every post to my Question helped me get to the final solution. I'd like to especially express thanks to digger who really honed in on the solution. Here is the code I ended up with:

#!/usr/bin/perl
use lib 'path\to\lib';
use Mail::Mailer;

$sender = 'sender@email.com';
$recipient = 'recipient@email.com';
$subject = 'test';
$message = 'test';

$smtp = new Mail::Mailer 'smtp', Server => localhost;

$smtp->open({ From => $sender, To => $recipient, Subject => $subject})
+ or die "Can't open: $!\n";
    print $smtp $message;
$smtp->close();

print "Content-type: text/html\n\n";
print "hello world<br/>\n";
[download]

Thanks again everyone! w00t!