Here's a project I've been working on for a few weeks now. Although it works, it's not 100% complete. When I'm finished, I plan to have support for RSS 0.9x/2.0, RSS 1.0, Atom 0.3, Dublin Core, RSS 1.0 Syndication Module, and RSS 1.0 Content Module.
This is not intended for webpages! This is supposed to be used as the parsing engine for RSS News Readers coded as a Microsoft Hypertext Application, or an application based on the Mozilla Application Framework.
I'm open to suggestions, bug fixes, bug reports, and other useful feedback for completing this project and making it bomb-diggity.
Both URL's bounce to the same place. Make sure to read all of the release notes before trying to use it. This code is released under the W3C license (which is one of the allowed licenses for MozDev.org projects).