The terms of the deal between Viacom and Joost were not made public but the service will have "free access to thousands of programmes and channels not readily available on the web".

The agreement reflects the growth of interest mainstream media is taking in online delivery of video.

Similar services

Services such as iTunes and websites from networks like NBC and ABC are turning to the web to offer programmes and films.

In the UK Channel 4 was the first of the main broadcasters to offer a video-on-demand service, while the BBC and ITV plan similar services for later in the year.

The content Joost will receive from Viacom is aimed at a younger demographic, with programmes such as Laguna Beach, Beavis and Butthead, Real World and Punk'd on offer.

Joost is still in a beta - or test - form, allowing users to give technical feedback to the developers.

The company recently announced a version of its software that will allow it to run on Apple Macs as well as PCs.

Janus Friis, founder of Joost said: "We built this platform from the ground up, with companies like Viacom in mind."

"We're extremely pleased to be working with Joost, and couldn't be prouder to be a key partner in the launch of the next generation in broadband video technology," said Philippe Dauman, Viacom president and chief executive officer.

There are also reports that Joost is in talks with British broadcasters ITV and Channel 4.