More Free Music Downloads
Blues Revue magazine regularly releases "artist showcase" announcements, with free downloads of mp3s from blues artists you may or may not have heard of yet. Not necessarily harp stuff, but it's one way to kind of keep up with new artists coming out, without investing anything. Ya never know....
http://bluesrevue.com/category/artist-showcase-download-free-music-here/#
You can also subscribe to their "e-zine" (Blues Wax), which has blues-related nterviews and articles (free).
Blues Festival Guide is also available online for free...not free tunes, but a good way to hear about not only blues festivals you might want to see (or participate in), but also some articles about artists and releases.