NetNewsWire Lite 1.0b14
NetNewsWire Lite 1.0b14 supports RSS discovery.
What this means in plain English is that, when you go to manually subscribe to a site, you can type just its URL, or even just a domain like www.someblog.com, and NetNewsWire will without fuss go ahead and find the RSS feed for you.
It doesn’t always work, unfortunately, but it works a great deal of the time. And it’s oddly addicting. (At least for me the developer.) Last night I spent some time going through the list of weblogs at weblogs.com just trying one site after another looking for RSS feeds. I found tons.