Will Johnson notes in a post to the OpenHouse Project mailing list that RSS feeds from Members of Congress are almost impossible to find and, "I’m pretty sure that some of the offices aren’t aware that their CMS [Content Management System] is generating a feed." To help out he has set up an interesting remix/mashup called PolFeeds, which grabs those feeds as well as those from candidates. He describes it this way:
PolFeeds. n. A website that brings you virtually all of the RSS feeds offered by Presidential Candidates, Members of Congress, and the White House together in one place.
In his post he describes a bit about how flexible this is:
If you want info from a particular politician, you can just go to "name.polfeeds.com". For example, barackobama.polfeeds.com will give you the content for all of Obama’s feeds, Twitters, YouTube videos, blog posts, Flickr photos, everything. Of course, you can limit your view to particular types of items. If you want to see only blog posts by House members, you can go to polfeeds.com/house/blog.
Appending "/rss" onto the end of any url will give you the rss feed for the items on that page. You can also subscribe to the feeds individually or create a custom feed. For example, you could put together videos from Pelosi with blog posts from McCain and press releases from Boehner.