One of the features of Expression Web is the ability to add xml files to your website and then to style that xml appropriately as html without needing to learn messy technologies like xslt. One of the things we have received feedback about in the product is that it can be hard to figure out how to use this feature with remote xml files - like rss feeds. One of our Program Managers, Andrew Jewsbury, has written a post in his blog about how to do just this. It's pretty neat, you should check it out.
Development Manager - Expression Web