Simple php problem.. need to add a BCC to mail script

i had this simple php mail script that i made from various tutorials and php.net … and it works great (i am sure it could be better/secure, but good enough for me… right now) anyways i need to now add a BCC with an email… and i can not figure out how to do it… here is the code i tried…

<?
$to = "my@address.com";
$bcc = "my@bccaddress.com";
$name = $_POST['name'];
$email = $_POST['email'];
$comments = $_POST['comments'];
$subject = "my site comments";
$Today     = (date ("l dS of F Y ( h:i:s A )",time()));

$message = "$Today 
";
$message .= "message result of contact form 

";
$message .= "-------------------------------------------------------- 

";
$message .= "SENDER : 
";
$message .= "$name - $email 
";
$message .= "-------------------------------------------------------- 

";
$message .= "COMMENTS : 
";
$message .= "$comments 
";
$message .= "-------------------------------------------------------- 

";

$header = "from: $name ($email)";

mail($to, $bcc, $subject, $message, $header);
header("Location: http://www.mysite.com/thanku.html");
?>

now from all i know about php… (and i don’t no much at all) this should work… but no… and i want to know why. Any help and or explaination would be very helpful… thanks in advanced…

Brian