What is RSS?
From whatisrss.com :
Why RSS? Benefits and Reasons for using RSS
What do I need to do to read an RSS Feed? RSS Feed Readers and News Aggregators
A variety of RSS Readers are available for different platforms. Some popular feed readers include Amphetadesk (Windows, Linux, Mac), FeedReader (Windows), and NewsGator (Windows - integrates with Outlook). There are also a number of web-based feed readers available. My Yahoo, Bloglines, and Google Reader are popular web-based feed readers.
Once you have your Feed Reader, it is a matter of finding sites that syndicate content and adding their RSS feed to the list of feeds your Feed Reader checks. Many sites display a small icon with the acronyms RSS, XML, or RDF to let you know a feed is available.