National Public Radio, together with it's television counterpart,  PBS, is the American equivalent and the nearest thing to the BBC. - Commercial free broadcasting and a focus upon quality, not quantity.

NPR's music have a live concert series called All Songs Considered, which has an eclectic mic of artists ranging from Sinead O'Conner to Wilco.

As well as broadcasting these concerts live, NPR also provide a full audio  stream of every show via their website...