$ch = curl_init("http://www.servidorremoto.com/upload.php");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CUROPT_POSTFIELDS, array('fileupload' => '@'.$_FILES['arquivo' ['tmp_name']));
echo curl_exec($ch);