Index: modules/upload/upload.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/upload/upload.module,v
retrieving revision 1.199
diff -u -p -r1.199 upload.module
--- modules/upload/upload.module	20 Feb 2008 13:46:42 -0000	1.199
+++ modules/upload/upload.module	20 Feb 2008 19:39:01 -0000
@@ -157,6 +157,7 @@ function upload_file_download($file) {
     return array(
       'Content-Type: '. $file->filemime,
       'Content-Length: '. $file->filesize,
+      'Content-Disposition: attachment; filename="'. mime_header_encode($file->filename) .'"',
     );
   }
 }