Watchcow is a simple and handy service (currently beta) which allows you to passively watch single Amazon products and entire wishlists in your newsreader, such as Bloglines (web), NetNewsWire (Mac), NewsFire (Mac) or FeedDaemon (Windows), just to name a few. It works with every newsreader/-aggregator that supports ATOM feeds. Which, incidently, means pretty much all of them.