I've been listening to music via the Royal Scottish National Orchestra website. The site has paid downloads at .99 a track and free one minute clips. As a collector, I don't find this particularly enticing. I doubt the selection is all that good for my interests and the free part of it isn't yet compelling, compared to say free Napster which I do revisit every week or so. There are a couple of Paul Lansky pieces though, in the 21st century section in what looks to be the catalog of Bridge Records. Actually, an interesting feature would be the ability to stream all the clips, rather than having to individually play them.
By the way, I never knew Antheil's full name was, as Paul Griffith's Classical Music Companion reports it, Georg Carl Johann Antheil -- a good German name for the New Jersey-born composer.