This is a good place to start learning about RSS is :
http://www.mnot.net/rss/tutorial/ As for publishing RSS. You just need to put the appropriate elements in the format. Get the example RSS 2.0 and fill in the elements.
If that is painful, you can try something like this
http://www.ajaxray.com/blog/2008/03/08/php-universal-feed-generator-supports-rss-10-rss-20-and-atom/ If you are looking to parse RSS from external sources, then use
http://magpierss.sourceforge.net/ Its got caching and other essentials that you would need for syndication.
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