Credit where it's due, it happened when I signed up for the "Help A Reporter Out" (HARO) site, which was put up by Peter Shankman. You basically get a couple of e-mails a day from Peter with literally dozens of requests for expertise on a broad variety of subjects. By being a qualified commenter and offering exactly what's being asked for you stand a pretty good chance of becoming a quotable resource. It worked extremely well for me -- this was my very first reply to a query.
Beyond my own plug, think about the application for your business's employment branding. Without depending upon a PR agency, you can get solid publicity for yourself merely by paying attention to a few e-mails each day and replying when you've got something to say.

