I've been talking a lot about RSS recently in relation to the Feeds Project, so here are some related links.

In order to use a feed aggregator, you have to be able to find the feed. Here are two tools to help you (if the site is missing an obvious link and Google doesn't do the trick):
- BlogStreet : RSS Discovery
- Syndic8.com - Welcome!

If you have no idea what I mean by "feeds" or "RSS," here's: All About RSS || Fagan Finder

Finally, if you're writing your own aggregator, you should probably pass this test suite (but I don't, yet):
- Aggregator client HTTP tests

and, if you're really cool, you can pass the autodiscovery tests for Atom (I'm not that cool):
- Atom autodiscovery test suite