You can create and customize your website's RSS or Atom feeds by generating digests with these online controls. Enter your URL(s) into Feed Scraper, work the controls, and...voila! Free and fee versions.
MagpieRSS provides an XML-based (expat) RSS parser in PHP.
MagpieRSS is compatible with RSS 0.9 through RSS 1.0. Also parses RSS 1.0's modules, RSS 2.0, and Atom. (with a few exceptions).