SimplePie: Super-fast, Easy-to-use, RSS and Atom Parsing
http://simplepie.org/

SimplePie is a very fast and easy-to-use class, written in PHP, for reading RSS and Atom syndication feeds. By keeping it simple, and focusing on what’s important, they have built a pretty sweet little API. SimplePie’s focus has been two-fold: speed and ease of use, and has been very successful on both fronts. SimplePie makes it easy to integrate syndicated content into your own website — and you don’t even have to worry about what kind of feed it is. SimplePie supports everything from the old-school RSS 0.91 and RSS 1.0 formats, to the ever-popular RSS 2.0 format, and also supports the emerging Atom format, in both 0.3 and 1.0 flavors. This has been added to Bots, Blogs and News Aggregators presentation resources page. This has been added to World Wide Web Reference Subject Tracer™ Information Blog.