A fast and easy to use PHP library for parsing RSS and Atom, written by Ryan Parman and Geoffrey Sneddon.

Features

• RSS 0.9x, 1.0, and 2.0
• Atom 0.3 and 1.0
• A handful of namespaces including Dublin Core, Media RSS, and iTunes RSS.
• Function names that focus on the data you want to grab, regardless of the feed type.
• Integrated support for mashing multiple feeds together and sorting them by date.
• Easy access to ALL tags/attributes in a feed.
• Extensibility allows for the addition of extensions/add-ons.
• Serialized caching system
• One-click subscribing to several online aggregators
• One-click bookmarking to several social bookmarking sites
• Embedded (or non-embedded—your choice) feed enclosures (Podcasting, Videocasting)
• Ultra-liberal Feed Locator (satisfies points 1-6 from Mark’s feed usability rant: http://diveintomark.org/archives/2002/08/15/ultraliberal_rss_locator)
• Image and favicon detection and caching
• Support for 100’s of character sets
• Support for PHP 4.3.2+, 5.0.0+
• Reasonable support for non-well-formed feeds
• Automatically strips potentially dangerous tags and attributes
• Supports parsing from a string
• Swap-in custom classes to replace built-in classes
• Supports gzip-compressed feeds
• Supports HTTP Conditional Get for more efficient caching
• Support for RFC 822, RFC 2822, RFC 3339, and ISO 8601 datestamps
• Plugins for several different blogging systems, wikis, forums, and frameworks.
• Able to extended to support new functionality.
• Comprehensive test suite (http://php5.simplepie.org/trunk/test/test.php)
• Well documented!