Here. Rory Blyth put the Amazon.com web service to work building RSS feeds to search for new products in your favorite categories, further pushing the “RSS as intelligent search agent” idea [1].
And, if anyone buys from links on his feeds, he promises to give the money to charity (until such time as it provides enough income for him to sip umbrella drinks on the beach, I presume : ).
[1] http://www.sellsbrothers.com/news/showTopic.aspx?ixTopic=703