I'm working on the instructions for a web site that aggregates blogs. We need to explain to users that they have to enter their RSS feed address in order for our aggregator to work. Problem is, not all blogging services make the feed address easy to find. Instead of just providing a link to the feed address, they use "chiclets" that automatically subscribe in Google Reader, Bloglines, etc. Does anyone know of a site where people can just enter a URL and get the feed address? I use Bloglines for this, but I'd prefer to reference a site that you don't have to register for. Alternately, I suppose if there's an API that would do this automatically so if people just enter their blog url instead of the feed address, our system could automatically convert it, that could work too. Thanks in advance for your help!