Hello, Nina!
RSS feeds are documents that very similar to HTML documents, but written in XML. I'm think, that main difference between RSS and HTML is in that RSS does not contain any information about how to show information, but only what to show. How to show RSS feed decide client program, special RSS reader or browser like Opera/Firefox. They contain something like header, where can be stored, for example, such information like a copyrights, author's e-mail etc. Main part of feeds consists of items. Information in every item written in the following parts: link, title of link and description of link or article. As you can see, it is very similar to what we see on linklists, news portals, forums and many other types of sites, it is one of reasons why RSS quickly become to a very popular format of information distribution.
Below is couple of links that can help you to figure out what RSS is and how it works:
http://www.sluttymiss.com/rss/ - this is a working "live" example of feed in format RSS 2.0
Use View->Show as text in menu to see internal structure of document.
http://www.christian-web-masters.com...l__page_1.html - here is a tutorial how to create basic RSS feed by hand.
http://blogs.law.harvard.edu/tech/rss - it is a RSS 2.0 specification. It contains description of all possible RSS tags written in more technical words.
Now, two words about software that can be used for RSS feeds creating.
Majority of RSS software that I saw in the net are just RSS readers, they are useless for RSS feeds creation.
Here you can find a program that will create RSS feeds semi-automatically:
http://feedforall.com/ You must enter a data (title, link, ...) manually to program and it will make a feed from them.
Program functions that create RSS feed automatically from existing database are usually just an add-ons to already existing software (forums, CMS...)
I wrote RSS part for my LL myself, using existing in X Power Links PHP functions for working with database.
If you have any questions about RSS feeds, just ask me.
Sorry for a long post and thank you for your attention
WBR, Alex