Radiohead have been pioneers in the online era after deciding to sell their last album from their own website in a pay-what-you-want offer before putting it out through a record company.
O'Brien said the Featured Artists' Coalition (FAC) had come about after a shift in the balance of power between artists and labels.
"The reason we can do all this is because the internet and digital technology have changed the landscape in the music industry, which basically means people can now release their music without a middle man, without a record company," he said.
O'Brien is on the committee's steering group alongside Blur drummer Dave Rowntree, Soul II Soul's Jazzie B, Billy Bragg, Marillion's Mark Kelly, hip-hop newcomer Master Shortie and pop star Kate Nash.
Nash said artists needed "a seat at this negotiating table".
"There are a lot of deals and decisions being made on our behalf that we have no say in," she said.
"The digital age has changed the industry so drastically and continues to change the world so drastically.
"That means there are more and more things coming up that decisions are being made on.
"It's our work, it's our life's commitment that is going to be affected so I think it makes perfect sense that we're there, saying this is what we think."
The FAC says artists are not routinely consulted in deals their labels and publishers strike with digital partners such as Nokia, MySpace and YouTube.
YouTube is currently embroiled in a row with the Performing Rights Society over how much money is paid to songwriters for the streaming of music videos.
Robbie Williams, who is believed to be preparing a new album, was the most high-profile star at the event on Wednesday. His next album will be his last under his current contract with EMI, after which he will be free to sign a new deal or release music in another way.
Pink Floyd drummer Nick Mason, KT Tunstall, Badly Drawn Boy, David Gray and Travis singer Fran Healy were also present, and were joined by dozens of up-and-coming artists whom the FAC is also designed to help.
Billy Bragg said the FAC would provide training for young acts to advise them not to sign away the rights to their recordings to labels for the current 50-year duration of copyright.
"The FAC will actually go out and mentor and educate young artists not to sign 'life of copyright' deals," Bragg said.
"What we need is an industry where the next Billy Bragg can make a living like I have for the past 25 years."
The body also hopes to have a voice in the current negotiations to extend the term of sound copyright, possibly to 70 years.
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