Creating a XML page

I was wondering if anybody has any good documents on how to create their own XML file to use for a RSS Feed. I want to learn more about how to create one from scratch or use some software to do this. I want to be able to modify it some to include different items and graphics into the feeds so any feedback would be great. I have seen a couple of packages out there, Feed for All and RSSLIBJ.
I am sure there are others out there I just haven’t ran across them yet. So if you know of any, send me a link. Thanks.
Dj