Not much can be found on the subject of creating eBooks in kindle/mobipocket. Much less is to be found about periodical format - i.e. the format in which Newspapers are published on Amazon. Yet the instapaper.com can do that and now are local www.idnes.cz do that also. How the hack can they do that?
(Periodical format of azw. is probably some extenstion of mobipocket format - but I'm looking for exact way to create such publication - with sections and articles exactly as for example The New York Times have)
The other way is to use Calibre directly
http://calibre-ebook.com/user_manual/news.html
you can even use this to download and prepare RSS feed, then edit the html and then compile to mobipocket:
Looks like the generated ncx wont work with kindlegen