MSN Search have put two new operators. And they work remarkably well !
Feed: Bring you raw XML or ATOM feed that contain your query terms.
Very impressive results where only Blogline and Findory can compete with it ! Blogpulse and Gigablast give you not so good results and Technorati is too slow to be an useful search tool.
You can combine with the [site:] operator to get all the feeds a site have.
HasFeed: Return any page* that links to an RSS or ATOM feed and returns for your query terms.
*Even if it's not appearing the page, ie an "link href" in the code will bring it : link href="http://site.com/feed.xml" rel="alternate" type="application/rss+xml" title="XML Feed of that page"