I was once again reading through the list of top 1000 blogs. This time I ended up on a website dedicated to helping reporters. Once you sign up, you'll start getting daily summaries of stories journalists are working on, with a note about the kind of people they're looking for to use as sources. If you can contribute, you contact the reporter directly.
I signed up a few minutes ago and will add a P. S. to this post once I've seen how interesting the e-mails are or aren't. I'm totally curious.