The BBC dress up their RSS feeds with XML stylesheets so they’re viewable in a browser as a page that has clear, readable content and a paragraph explaining what it is. This is a excellent practice; typical users will be confused when faced with raw XML data and assume that something has broken, which, in a way, it has.
I must try to do this. The BBC are using XSLT, a rather heavy official XML format for transforming XML, but there is also a lighter, simpler alternative: ordinary CSS. Ben Hamersley has written a quick intro to using CSS to present XML on OReillyNet.