AARP, no kidding. It is free, powered by Slacker. I'm listening to Art Tatum right now.
Programing is by Concord, which now owns a boatload of valuable music.
Edit: In this relaxed setting I am appreciating "Freddie Freeloader" more than I ever have before. Go figure? I think I like Internet radio. Unlike broadcast, I can click next if I don't like what comes on.