The BBC is experimenting to create an iTunes for the broadcast industry.
The company is looking for 5,000 broadband users prepared to take part in a three-month content trial of its technology, which is called Interactive Media Player (IMP).
Macs aren't supported, at least during the trial period. A BBC spokesman told Macworld: "We won't be able to offer the IMP pilot to Mac users during the three month trial, I'm afraid."
He promised this may change, should the service trial succeed, he explained: "However, we are aiming to make it available should the service roll out fully."
Dot Cotton goes online
This technology lets UK viewers catch up on TV and radio programmes they may have missed for up to seven days after they have been broadcast, using the Internet to legally download programmes to their home computers. After seven days built-in rights management features disable the downloaded clips.
The BBC will offer 190 hours of TV programming and 310 radio shows, including EastEnders and Top Gear, as well as movies. The trial begins in September.
The test group will be able to search for programmes they want to see, filter shows by channel, initiate subtitles and be able to collect and watch episodes of series they have missed.
"IMP could be iTunes for broadcaast"
Ashley Highfield, BBC director of new media and technology, said: "IMP could just be the iTunes for the broadcast industry, enabling our audience to access our TV and radio programmes on their terms - anytime, any place, any how - Martini Media."
"We'll see what programmes appeal in this new world and how people search, sort, snack and savour our content in the broadband world."
Highfield joined the BBC in October 2000 and is a member of both the BBC's Executive Board and its Creative Board.
He is responsible for the BBC's output on the internet and interactive TV, as well as new and emerging platforms such as mobile and broadband.
The number of UK adults visiting bbc.co.uk has more than trebled from 4.6 million to 14.4 million monthly users since Highfield joined the company.