Attaching a zip file

I looked at the examples, but I can't seem to make it happen.

It would seem to me I would want to file_get_contents, but this does not seem to work.

$attachment=array(
"Data"=>file_get_contents($_SESSION['attachment']),
"Name"=>"pics.zip",
"Content-Type"=>"automatic/name",
"Disposition"=>"attachment"
);
$email_message->AddFilePart($attachment);

Never mind. That code works. It helps to have data in the attachment stream.
:o)