I picked up a book on XML, but there was nothing in it about SEO. I know if a site can get visited often, it can make money. Is duplicate content a problem?
RSS is a great tool when used in the right places. I'm not sure if there is "money in it" but I can be used with great effect within SEO and online marketing as it makes syndication of your content immediate.
It’s quite simple to create a php script that takes pages from your site and turns it into a rss file especially if you have news type listings on your site already.