This web part serves as an alternative for the MOSS RSS Viewer web part, especially if you do not have MOSS or if you need to display RSS feeds on a WSS site. I needed to write this web part for that exact reason, I didn't have MOSS and I needed an RSS web part on my WSS site. The web part is Ajax enabled for faster page loads.
Check out http://philwicklund.com/freeware/rssreader
to view a more detailed feature description, screen shots, and a working example. Go to http://philwicklund.com/freeware
to view my other free offerings.