This is the site I first used to learn it -
http://cyber.law.harvard.edu/rss/rss.htmlAn RSS file, to be dynamic, needs to be written with a server side language. You can either overwrite a file called whatever.xml for example, or you can simply offer a PHP/ASP file as an RSS file and just change the header to output the file as XML. The each item is just built using your script just like a list of results would be built.