Index: wp-admin/plugin-editor.php
===================================================================
--- wp-admin/plugin-editor.php	(revision 6829)
+++ wp-admin/plugin-editor.php	(working copy)
@@ -141,7 +141,7 @@
 	?>
 	</p>
 <?php else : ?>
-	<p><em><?php _e('If this file were writable you could edit it.'); ?></em></p>
+	<p><em><?php _e('You need to make this file writable before you can save your changes. See <a href="http://codex.wordpress.org/Changing_File_Permissions">the Codex</a> for more information.'); ?></em></p>
 <?php endif; ?>
  </form>
 <?php