I hope this helps some people with sending html messages.
// Send to multiple people, just put a comma and a space between them.
$mail_To = '"'."Name".'"'." <email_Address>";
$mail_Subject = "Subject";
// I use used Unix Date/Time Stamp as my boundary
$message_Boundary = date("U");
//
$mail_From = "From: return@emailaddress\n";
$mail_From .= "User-Agent: Apache/PHP\n";
$mail_From .= "X-Mailer: PHP/".phpversion()."\n";
$mail_From .= "X-Accept-Language: en-us, en\n";
$mail_From .= "Mime-Version: 1.0\n";
$mail_From .= "Content-Type: multipart/related;\n boundary=".'"'.$message_Boundary.'"';
$mail_Message = "
--".$message_Boundary."
Content-Type: text/html;charset=US-ASCII
Content-Transfer-Encoding: 7bit\n";
// you can send images incoded into the message also, but I haven't.
// example of this is at this location http://www.ietf.org/rfc/rfc2557.txt
$mail_Message .= "HTML code";
$mail_Message .= "\n\n--".$message_Boundary."--\n";
mail($mail_To, $mail_Subject, $mail_Message, $mail_From);