From the CSMonitor:

"An RSS file is basically a list of headlines encoded so that it can be easily used by another program or website. RSS is usually said to stand for "Really Simple Syndication" and it is relatively easy to implement and use. RSS is a form of XML (eXtensible Markup Language), which means that each piece of data in the list — a headline, a description of a story — is coded separately so that a program will know exactly what to do with it.

Programs that know what to do with RSS files are called "news aggregators." They let you read headlines from dozens or hundreds of news sites at one time. You simply plug in the addresses of the RSS files you want, such as the ones listed above.

News aggregators are proliferating, for a variety of platforms and degrees of technical expertise. Some popular ones are Amphetadesk (for Windows, Linux, or Mac), Radio (for Windows or Mac), NetNewsWire (for Mac), KlipFolio, NewzCrawler (for Windows), and FeedReader (a bare-bones Estonian PC version). [If you use Mozilla Firefox, their is a internal rss reader found here.]

If you don't want to install any software, you might try a free website Bloglines, which offers a simple way to read RSS files in your browser. There's also Oddpost (for Windows), a web-based e-mail service that includes a built-in aggregator.

Five software packages that require a bit of technical knowledge are Syndirella, Aggie, NewsGator, SharpReader, and Wildgrape News Desk (all require Microsoft's .NET to be installe\d on your PC). A Java installation is required for nntp//rss, a program which lets you read RSS files in Outlook Express or any other newsgroup-reading software. Or if you'd like your RSS headlines in a news ticker, try wTicker (for Windows).

Once you have one of these aggregators installed, click on the 'Subscribe' button. It will take you to a page where you can add the RSS feed to any of the most popular aggregators with one more click. Or you can copy the URL from the little orange XML logo next to the RSS feed you wish to read, and add it to your aggregator manually. This is a slightly different process for each aggregator, so look to the help files that come with it."

For more information on RSS, check out this site.