If you want to listen to internet audio programs (podcasts) music and shows but can't listen to them when they are scheduled this program is for you. iPodder is the premier Podcasting application, allowing users to capture and listen to Internet audio programs anytime, anywhere. It allows users to select and download shows and music and to play whenever they want on their iPods, portable digital media players, or computers automatically, after specifying which music or shows they want to listen to. It supports most RSS protocols and scans for enclosures

renko - a simple enclosure-aware RSS aggregator/downloader

OpenSearch is a collection of technologies, all built on top of popular open standards, to allow content providers to publish their search results in a format suitable for syndication. Any site that has content and a search box can choose to return results in OpenSearch RSS. This includes travel sites, classifieds, encyclopedias…. If you can provide search results for something, it probably can fit into the OpenSearch model. Returning OpenSearch results is easy—the format is the standard set of XML elements, plus three additional elements designed to support navigation between pages