In the good old days (just a few months ago), anyone who wanted to watch particular TV shows had a narrow window of opportunity – according to someone else’s programming timetable. And they could only do it one program at a time.

Enter Joost, the latest venture of the successful team that brought you the pioneering Kazaar file sharing program and Skype phone service that millions of people around the world now use to make their telephone calls via the internet. Having sold Skype for a reported $US2.6 billion, Niklas Zennström and Janus Friis have turned their attentions to the next big online thing: Joost internet TV.

Joost is not like other television services, like traditional free-to-air or cable-based pay-TV. It does not operate to set programming schedules and it is not restricted to a handful of channels offering the same tired old programming. If any new cyber-age product ever deserved to be described as "revolutionary", Joost certainly does.

For a start, Joost has already lined up hundreds of distinct TV channels and its creators plan to boost the list to thousands over the next few years. That alone is staggering enough, but add to it the fact that Joost allows you to access any program on any channel you want, 24 hours a day, 365 days a year and you start to get an idea of what is taking place.

Not only will any broadband internet user be able to access thousands upon thousands of programs, movies and videos, but they will be able to pause any of them at any time, and come back hours or even days later and start viewing again right where they left off. Getting a bit bored with the slow pace of the program you have chosen? You can fast forward to any point in the program you want. Still too slow. You can jump ahead five, 10, 15 minutes at a time. The control that Joost gives a viewer over whatever they want to view is simply staggering. It is what video-on-demand always promised for the far-off future, but the difference is it is being made a reality right now.

If you are able to get an invitation to Joost’s beta service from a friend or one of the links that have been published in computer magazines, you can get started right now. And, perhaps most attractive of all, unlike pay-TV, Joost is free, supported by an occasional advertisement.

Even with the beta service, when you have downloaded the software that runs Joost TV, you will have a choice of dozens of programs in each of the services main categories: comedy, music, documentary, cartoon and animation, entertainment, lifestyle, sports and games.

Among them there are already some familiar names like CNN, National Geographic, MTV, National Lampoon and so on (although the bad news for international viewers is that many of these are currently only available in North America due to copyright licensing restrictions). But there are still many channels available even overseas, and the number is growing daily. They include more music video programs than you could ever get through, the Movieola short film channel with seemingly countless short films, the Alliance Atlantis Sci-Fi Channel with dozens of science fiction programs. The list goes on. Although there are probably many worthwhile programs on Joost, the potential for time-wasting is enormous already and is set to grow over the coming months and years.

If you are a parent hoping that the service may collapse under the demand that it is bound to attract as it becomes better known, you may need to think again. The service, created by a group of 60 top engineers, is designed to improve as it grows. The reason is that rather than being based on a single broadcasting source it is distributed in the same way that many file-sharing services are run: via peer-to-peer networking. This means that users of the Joost software do not simply download programs to their own computer, but also re-broadcast it to other users of the service in a never-ending chain.

Although some doomsayers have suggested that this process could eventually bring the internet itself to a grinding halt by clogging up its main arteries, there is certainly no sign of that at present, and given that the same prediction has been made over and over again as the internet has moved into new forms of content, it is probably unlikely to happen. For a start, too many major corporations now rely on the internet to allow it to grind to a halt. And governments all over the world have also placed too many critical services online to allow it to fail.

The fact is that parents have to start grappling with the impact of the new multimedia monster before it overwhelms their children. But the bad news gets worse. Joost, of course, is not the only online video or TV-style service available on the internet. Mainstream television stations are already getting in on the internet act by broadcasting their own shows online. Most news and current affairs programs have an internet service for those who missed the TV broadcast and many other programs are placing much of their footage online.

Most parents already know of internet video services like My Space and Youtube, but many have not kept up with the evolution of these sites. As most would know, the sites started out allowing anyone with an internet connection to upload their amateur videos for others to watch. Inceasingly, though, both services have allowed professional and commercial content to be added. including just about every music video ever made and episodes of television programs from the Monty Python Show to Fawlty Towers. And such sites are only the best known ones. There are many more catering to specialised tastes.

Even Joost-style, peer-to-peer TV has imitators. The list already includes services like CoolStreaming, Cybersky-TV, Babelgum, LiveStation, PeerCast, ReelTime.com, TVants, and Tvuplayer, to name just a few.

Possibly the most ironic thing for parents is that the computers they have provided to help their children complete their school work are fast becoming the biggest distraction of all, dwarfing traditional distractions like music, radio and regular television. The main reason, of course, is not just the huge amount of material available, but the fact that it is available on demand. You can get it whenever you want. It would clearly take a very disciplined child who has access to the internet to resist the temptation.

Fighting the distractions will require parents to adopt a whole new mindset about the organisation of the family’s electronic and computing resources. Parents who bought a standard Windows-based computer for their kids to do research and type up essays will need to explore new ways to achieve this end which do not involve open-ended internet access.

One measure that some parents are already taking is to choose a computer with restricted capabilities. For instance, there is the "parental control" software included in Windows Vista or other third-party software that is now available, including programs like Safe Eyes, CyberPatrol and CYBERsitter. Unfortunately some of the software currently available has flaws which allow tech savvy kids to get around restrictions. Nevertheless, this is one possible approach for parents who are willing to do their homework.

Another option for the more tech savvy parents is to experiment with an operating system like Linux which now comes in many flavours, some of which, like PCLinuxOS or Ubuntu, are very user friendly and can be used to thwart access to online TV. Unfortunately, even though Linux is much easier to install than it used to be, some parents may still lack the necessary computing skills.

One alternative on the horizon is the introduction of a new range of stripped-down computers that is soon to be released. The one that has received most publicity is the Asus "eee" laptop computer. This computer will come with a version of Linux already installed that will allow kids to do their school work, but which is unlikely to run the software required for services like Joost.

One of the big attractions of the eee laptop is that it is expected to be very affordable. Early indications are that it will sell for around US$200. One reason is that it will be sold with a small screen (around 7-10 inches) and a small keyboard as well. However it will come with VGA and USB ports that will allow a regular monitor and keyboard to be attached.

Other budget machines are sure to follow and because manufacturers will need to keep costs low, they are also likely to run free Linux-based operating systems that will not run multi-media and online television software designed for Windows.

So hopefully parents will soon have the option of purchasing cheap, stripped-down computers that will shield their children from the temptations of limitless TV and video offerings.

Another option could be for parents to provide internet access with restricted downloads. Dial-up internet access, for instance, is too slow for most video or TV services. Another option is fast broadband access with low download limits. Some accounts are restricted to around 500 megabytes, which is plenty for most kids to do their homework, but if they start watching online TV the 500 megabytes will be quickly used up and access will be shaped to a much slower speed – too slow to watch any more TV.

Whatever course parents adopt, it is clear they will need to stay informed about the latest online developments and take an even closer interest in what their children are using their computers to access. One thing is certain: the world of home entertainment will never be the same again. You will soon find yourself in the middle of yet another online revolution, ready or not.