Bored because there’s nothing on the box? That could be a thing of the past if Joost, a new internet TV service succeeds in shaking up the television establishment. From big-budget dramas to niche documentaries, the people behind Joost say they will provide a huge array of TV programmes straight to your computer, wherever you are and whenever you want, at full screen, and at broadcast quality. Best of all, this will all be free to the viewer.

TV bosses are taking the threat of Joost particularly seriously because the Scandinavians behind the project have form. Niklas Zennström, a Swede, and Janus Friis, a Dane, have made a habit of scaring established industries with their web revolutions. Their file-sharing website, KaZaA, did serious damage to the music industry. Then Skype, which lets people make free telephone calls using their computers, began to eat into the business of traditional telecoms companies. After selling Skype for $2.6 billion, they’re now taking on the broadcasters, and yet again, that can only be good news for you and your wallet.

With Joost, though, they say they don’t want to destroy TV as we know it, merely give it a boost. They want to mesh the best aspects of watching TV at home with the best of what the internet can provide. "TV is mainly about leaning back and being entertained," says Fredrik de Wahl, chief executive of Joost, rather than "leaning forwards" and having a sneaky peek at a YouTube video at work when you think the boss won’t be watching. "[With Joost] you’re not forced to interact, but if you want to, you can".

So Joost will have "channels" just like normal TV, huge playlists of videos that you can flick through in case you don’t know what you want to watch. "When I come back to my room and switch on a TV,” Mr de Wahl says, “I don’t want to get a web browser, I want to start watching a show. We want to replicate that".

If you do know what you want, there’s a search function that will help you locate it. If, for example, you have an unhealthy interest in squirrels, you can search for all the programmes about squirrels there are out there. Not only that, Joost will instantly create a squirrels channel for you that will update with new programmes about squirrels when they become available.

Excited by this prospect, 400,000 people around the world have signed up just to test the product. Joost aim to unleash it globally ("you never really ‘release’ software, you unleash it" de Wahl says, ominously) by the end of June this year. The likes of Viacom – who own MTV, Nickelodeon and Paramount Pictures – and Endemol, the makers of Big Brother have already signed up to show their programmes on Joost. The BBC says that it’s holding informal talks with Joost, and the company has reportedly spoken to ITV and Channel 4 about screening their programmes.

How can it all be free? Well, because we’ll still have advertising breaks, between one and three minutes per hour, so you’ll still be paying, just with your attention. Even then, Joost says, you’ll actually want to watch these adverts, because advertisers will have the ability to work out, for instance, how many Friends viewers there are in a particular postcode, so they can target their adverts specifically to those viewers.

Joost argue that this is a win-win situation for all involved. The adverts will generate revenue to pay the makers of expensive shows such as Desperate Housewives or Lost. The advertisers get better value for money as they can reach the exact audience they want to get to, and we, the viewers, get everything we want without paying.

Some broadcasters are more sceptical about Joost’s money-making model. Stephen van Rooyen, Director of Product Management at Sky, said: “How will Joost convince the producers of King Kong – which took around $200m dollars to make – to give it away for free? Are there enough marketing dollars to subsidise TV to the viewer?”

We’ll soon find out. But Joost isn’t the only one trying to make this idea work. Babelgum are trying to use exactly the same "peer-to-peer" technology to establish a rival to Joost. Its TV service will also be free, and though it is less developed than Joost’s, they’re also already snapping up deals with programme makers from around the world. So if you don’t find what you want on Joost, you might just find it on Babelgum.

So, is that it then? Should we rearrange the furniture in the living room and point our sofas to our PCs instead of our TVs? Not quite yet.

"This is a bit like saying the electric car is here, this is the death of petrol car," argues Simon Calver, chief executive of Lovefilm, an online DVD rental company that recently announced a download-to-burn film service. Calver thinks that people will be unwilling to give up their flat-screen, HD-ready TVs and DVD players until the internet can provide an experience that equals or exceeds what they’re used to.

That problem niggles. The thing missing from this new way of watching television is the TV set itself. But even here, the technology is gaining ground. Apple is, as ever, at the forefront. It is launching Apple TV this month, a set top box that will hook up your computer to your television. Using a remote control, you’ll be able to sit back and watch films and shows downloaded through Apple’s iTunes software on your normal TV (although the geeks testing Joost have already hacked into Apple TV so you can watch Joost through it as well, something that will infuriate Apple’s bosses).

Proponents of web-based TV say that the problems with hardware will be resolved once the system is up and running. "Look at Skype," says Erik Lumer co-founder and chief executive of Babelgum, Joost’s main rival. "Once you have a service that is easy to use and that you don’t have to pay for, all of a sudden manufacturers start creating cordless phones you can use with Skype. The same thing will happen with TV."

So the trend seems clear. Soon the likes of Joost and Babelgum won’t just be for computer nerds who are more comfortable clicking a mouse than jabbing at their remotes. Yes, you’ll be able to be involved with chat rooms discussing Sarah Jessica Parker’s latest outfit in Sex and the City, while watching the show with people from around the world. But you won’t have to. And instead of explaining why your friend absolutely has to see latest episode of Big Brother, you’ll just be able to send it to them so that they can see for themselves. If it succeeds, it will be a big step forwards in the evolution of television.