UPDATE with JOIN

Hi All,

I am banging my head againset the wall trying to figure out how to do a JOIN
within an UPDATE.  Can someone please help me out?  Here is what I have.  Of
course it does not work. :-(

UPDATE tbl_line_item
   SET tbl_line_item.reviewed = TRUE
  FROM tbl_item
    ON ( tbl_line_item.item_id = tbl_item.id )
 WHERE item_type = 'DIR';

Kind Regards,
Keith