Buradan göz atabilirsiniz .. http://tr2.php.net/manual/en/function.header.php

Örnek kodlar
// We'll be outputting a PDF
header('Content-type: application/pdf');

// It will be called downloaded.pdf
header('Content-Disposition: attachment; filename="downloaded.pdf"');

// The PDF source is in original.pdf
readfile('original.pdf');
?>