I use Mail::Sender pretty extensively. Here's a code snippet to get you started for sending an email with an attachment. (We let the user's email client determine the helper application to execute based on the file extension of the filename we attach to the message.)

Mail::Sender lets you customize the MIME stuff, but for simple single files you don't need to do that.

sub send_email
{
    my $sender = new Mail::Sender({
        from => $from_address,
    });
    $sender->OpenMultipart({
        to => $to_email,
        subject => $subject,
    });
    $sender->Body;
    $sender->SendLine( $msg_body );
    $sender->SendFile({
        description => 'Raw Data File',
        encoding => '7BIT',
        file => $tempfile,
    });
    $sender->Close;
}
[download]

I really like this module. You should seriously consider installing it if you find that you are doing a lot with emailing attachments. It has saved me tons of time.