WXPR is a small, unaffiliated public radio station broadcasting form a small town in northern Wisconsin. Most of its programming is done locally, and it's really good.
The Blues Friday show is broadcast every Friday form 6PM to 11PM, central time. It is the best blues programming I've ever heard on any radio station.
Here's a link to the show's website. You can stream the show. It's worth it.
I also recommend the excellent Saturday afternoon bluegrass show.