The "Rock and Roll Geek Show'' broadcasts twice a week from San Francisco. But you won't find its distinctive mix of good time rock 'n roll, beer and Macworld commentary anywhere on the radio. ¶ The half-hour show, hosted by Michael Butler, is delivered directly to listeners' iPods and other digital music players. It's among a growing number of ``podcasts,'' a new online outlet for amateur broadcasters to run their own pirate radio stations. No government approval required. ...¶... It's hard to imagine giant radio conglomerates like Clear Channel Communications fretting over such harmless-sounding podcasts as ``The Dawn and Drew Show.'' But technology can pounce on unsuspecting, entrenched businesses. And podcasting seems to hold the same disruptive potential as TiVo, giving everyone the power to listen to the radio shows they want, whenever they want. ... Link: MercuryNews.com.