I would like a suggestion on the existing public web services like the ones from Google, Yahoo, Amazon, Flickr etc. that can be used in a web service composition engine. Would prefer to use those that do not require authentication, but this is not mandatory. I am looking for a real case study that would use at least 3-4 web services. Like for example: I want to visit a town in a foreign country and would combine the directions and places web service API's from Google. Much appreciated. Thanks.