Roger's advice is the best. Search, and also read thoroughly the mail doucumentation and user notes at php.net
Here are some more "hints". 🙂
I think you have the parameters for "mail()" wrong; it should be "mail($sendTo, $subject, $message, $headers)". Concatenate the "$cc" into "$headers":
$headers .= 'Cc: ' . $_POST['email'] . "\r\n";
I'm told some filters will mark as spam, or some servers won't accept, mail that has no "Message-ID:" line. Try adding this (with the appropriate translations, of course) to "$headers":
$from_arr = explode('@', $_POST['email']);
$server = $from_arr[count($from_arr) - 1];
$msg_id = uniqid('') . '@mail.' . $server;
$headers .= 'Message-ID: ' . '<' . $msg_id . '>' . "\r\n";
Be sure to put two "\r\n" at the end of the headers.