From the standpoint of the client (download is always done by software playing the role of the client), there is no such thing as "PHP page". For a client, all pages are the same. HTTP is HTTP.
If you want do download anything with PHP, look here:
http://php.net/manual/en/function.fopen.php[
^]. There is a download sample on this page, please find it. Basically you simply open a stream and binds with any resource by its URL, depending on the URL scheme you use. This is transparent to the downloading code.
—SA