$boundary = md5(microtime());

$headers .= 'From: Biotech Association of Maine<noreplay@here.com>' . "\r\n";
$headers .= 'MIME-Version: 1.0' . " \r\n";
$headers .= 'Content-Type: multipart/alternative; boundary="' . $boundary . '"' 
. " \r\n";
$headers .= $body;
$headers .= "--$boundary \r\n";
$headers .= 'Content-Type: text/plain; charset=iso-8859-1' . " \r\n";
$headers .= 'Content-Transfer-Encoding: 8bit' . " \r\n";
$headers .= $body . "\r\n";
$headers .= "--$boundary \r\n";
$headers .= 'Content-Type: text/html; charset=iso-8859-1' . " \r\n";
$headers .= 'Content-Transfer-Encoding: 8bit' . " \r\n";
$headers .= $htmlbody . " \r\n";

$headers .= "--$boundary-- \r\n";