The Web service RSS feed web part can be used to create an RSS feed of data provided by an external web service. It uses a built-in web service data source as a source of the feed data. It displays a link leading to the feed, which is located at the URL of the page where the web part is placed, with a querystring parameter appended.
Help URL: http://devnet.kentico.com/docs/webparts/index.html?WebServiceRSSFeed_overview.htm