Nope, the Mime and content-type stuff has to go in the additional headers parameter, not the message body parameter:
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$headers .= "From: $from";
$message = '<html><body><a href= "http://www.google.co.uk">www.google.co.uk</a></body></html>';
$mails = mail($to, $subject, $message, $headers);