Here’s a new option to look into for your RSS parsing coding needs, particularly if you want to share a desktop and iPhone code base:
FeedParser, a brand new NSXMLParser-based RSS parser for Cocoa, has been released as an open source project on GitHub. The goal of this project is to provide an extensible RSS/Atom parser that works on both the iPhone andthe desktop. To that end, it is based on NSXMLParser instead of NSXMLDocument. I recognize that PubSub is available for the desktop, but FeedParser was designed primarily with the iPhone in mind.
In its current incarnation, FeedParser understands all of RSS 2.0 (although it does not expose all of the possible fields). It has also been verified to correctly parse sample RSs 0.91 and RSS 0.92 feeds. It has minimal support for Atom (to the extent that it understands <atom:link> elements embedded in RSS feeds), but the architecture is such that Atom support can be added over time. It also has support for RSS extensions such as DublinCore…
Code is on github and MIT-licensed.