The mail function has an option to add a Bcc or Cc. 

I have been using that only to find that thought the headers on the original message are ok, a copy to neither the Bcc or Cc reach their destination. And yes, I use the \r\n in the headers

I use PHP 4.3.2 on RH8

I just tried PHPmailer class with the same result!

Is this a PHP 4.3.2 bug?

The script I use is:
mail('jadoo@xs4all.nl','Subject 2-2', 'Your message here.',
    "To: Travel Jadoo <jadoo@xs4all.nl>\r\n" .
    "From: The Webmaster <webmaster@traveljadoo.com>\r\n" .
    "Cc: Interested <alfredtuinman@xs4all.nl>\r\n" .
    "Bcc: Me Too <alfred@odyssey.co.in>\r\n" .
    "X-Mailer: PHP 4.x");