Despite the all-pervading influence of television ninety per cent of people in Britain still listen to the radio, clocking up over a billion hours of listening between us every week. Its a background to all our lives: we wake up to our clock radios, we have the radio on in the kitchen as we make the tea, its on at our workplaces and in our cars. From Listen With Mother to the illicit thrill of tuning into pirate stations like Radio Caroline; from receiving a musical education from John Peel or having our imagination unlocked by Douglas AdamsThe Hitchhikers Guide to the Galaxy; from school-free summers played out against a soundtrack of Radio One and Test Match Special to more grown-up soundtracks of the Today programme on Radio 4 and the solemn, rhythmic intonation of the shipping forecastin many ways, our lives can be measured in kilohertz.Yet radio is changing because the way we listen to the radio is changing. Last year the number of digital listeners at home exceeded the