Future Radio - The Washington area seems to be the epicenter of the digital radio --- ummmmm --- revolution. Right, that's it. I regularly see stories about local venture XM Radio, which works something like DirecTV for radio by delivering 100 channels of satellite audio programming (usually to your car). Thank god I don't commute enough to need that. XM is struggling to jump start an expensive luxury technology in slow economic times and competitive market. Not helping is another local firm, iBiquity, which offers a terrestrial technology to let ground stations simulcast analog and high-definition digital signals. Seems like any success the latter has is going to mean trouble for the former and eventually D.C. will be left with one less company (if not two).