Hi Richie,
I think I've solved the problem. In the mail function put an extra header 'content-type:text/html'. It'll work. I'm pasting below a sample code which I tried and it works.
<!doctype html public "-//W3C//DTD HTML 4.0 //EN">
<head>
<title>Title here!</title>
</head>
<body>
<?php
$to = "nilesh@sapna.com";
$subject = "test";
$message = "<main><title></title></main>\n";
$message .= "<body><strong>Hi There</strong></body>";
$type = "Content-type:text/html";
if(mail($to, $subject, $message)) {
echo("Mail successful");
}
?>
</body>