The BBC says it has received a huge response from viewers willing to try out the second phase of its new service offering catch-up TV and radio.
Volunteers will give their opinions of the service to the BBC.
The Integrated Media Player (iMP) is being sent to volunteers' computers this week, after 5,000 were chosen from a total of 30,000 who applied.
The player enables UK users to view and listen to TV and radio via the web for seven days from the original broadcast.
Volunteers' viewing habits will be checked to help gauge public interest.
The service will be sent out to the shortlisted 5,000 - who have been chosen as a representative sample of the UK - over the next two weeks.
Tony Ageh, BBC controller internet, said: "This response has been fantastic.
"There was a sense from the first technical trial that a catch-up TV and radio service would be extremely popular with people.
"It has the potential to truly revolutionise the way that people watch and listen to programmes."
The BBC will monitor the volunteers' viewing habits and record their opinions on iMP until the end of the year.
The trial period will determine whether there is enough public interest in iMP for a full roll-out of the technology and the potential market impact.
During the first phase of the trial, which ran for three months during the summer of 2004, 75% of people taking part felt the BBC should provide the service.