HTML Tags around content and Email Address in email

Hello all. I’m processing a simple flash email form with php, but for some reason when I receive the email, it has this strange html code surrounding the content and the persons name who sent it. Also, when I click reply to, it puts the persons email address, but it all puts this long string of strange HTML markup. I’ve been trying to figure this out for about 2 hours now and cannot crack it. Any help would be appreciated. Here is my code.

<?php

$to = "yourname@mydomain.com";
$subject = "Website Inquiry";
$msg = "$name

";
$msg .= "$phone

"; 
$msg .= "$email

"; 
$msg .= "$comments

"; 
mail($to, $subject, $msg, "From: $name
Reply-To: $email
Content-Type: text/html; charset=iso-8859-1");

?>