Channel 4 has set up an internet radio station, taking the first step towards plans to become a major force in radio.
Listeners will get radio shows devoted to TV hits such as Lost
Channel4radio.com offers shows that tie in with its flagship TV hits including Big Brother, Lost and Channel 4 News, as well as original programming.
The broadcaster eventually hopes to launch a series of Channel 4 radio stations that will be available on DAB digital radio and digital TV.
Channel 4 said there was a demand for speech and non-formulaic music radio.
The shows available include a daily Big Brother round-up, UK Lost - featuring fans' discussions and sneak previews - and Richard and Judy's Audio Book Club.
Original programmes include Secret Confessions of... - anonymous diaries by teachers, police officers and other public servants - and entertainment round-up The Glory Box, presented by Rick Edwards.
Users can either listen over the internet on their computers or download the programmes to listen to on MP3 players or mobile phones.
Some shows will also air on existing speech-based digital radio station Oneword - in which Channel 4 has a majority stake.
"Channel 4's ultimate objective is to contribute something new to the radio mix," chief executive Andy Duncan said.
"We believe there is a gap in the market for contemporary speech radio services - offering an alternative to what the BBC has to offer across news, current affairs, comedy, entertainment, lifestyle and many more genres - as well as non-formulaic music radio.
"We want to add to what commercial radio has to offer by extending its programming range, introducing an exciting line-up of new and established talent and deepening its relationship with its audience."
Channel 4 will lead a consortium to bid for the second national DAB multiplex this year - which would give it a block of digital radio frequencies if successful.
Channel 4 Radio will be helped by the recruitment of former BBC Radio 2 controller Jim Moir as a consultant.