Watch TV on your PC whenever you like

The small print
Of course, there are some limitations to streaming TV. Most importantly, free programmes are normally made available to watch for a limited period of time.

Even if you are allowed to download free video files for viewing later, digital rights management (DRM) technology is used to make sure the file can only be viewed a certain number of times, or for a set time period. So you cannot build up an archive of old TV shows like you could with a VCR.

Also, the on-demand catalogues of TV stations do not usually include movies, so you will need to go to dedicated movie download websites ­ – we will explain how these work later.

Streaming television programmes on several different computers (one at work and one at home, perhaps) is normally simplicity itself, but it’s important to note that downloaded movies and other programmes that are saved for future use can be more troublesome. Many services that sell downloads use DRM techniques that tie them to one PC, or a limited number of devices, so moving to a new PC can be a pain.

What’s on for free
For free on-demand TV, the major terrestrial channels: BBC, ITV, Channel 4 and Five, all provide their programmes, at no charge, via online streaming.

The best known is the BBC' s iPlayer service. This service does not require any kind of sign-up and everything is free. On-demand programmes are available for seven days after broadcast, and downloaded videos (for which you need to download the free iPlayer Desktop software) must be viewed within 30 days. Optional parental controls are available to stop children accessing adult-rated shows.

ITV Player has a huge 30-day library of free catch-up programmes, but you cannot download programmes to watch after this period or when you might be offline. No registration is needed, but there are optional parental controls.

Channel 4's 4OD has no download or registration requirements, but does offer a great free catalogue of shows going back well over 15 years. It is not the easiest site to use, though, with a very modern-looking but unusable design. Parental controls can be set up, with a security code used to allow adults access to all shows.

Demand Five offers a mix of free and paid-for shows that you can either rent for 14 days or buy to watch forever. You need to be over 18, create an account and download the Demand Five Player software to download shows.

Blinkbox focuses on paid-for movie streams, but also offers TV programmes, many of which are free.

Lovefilm is best known as an online DVD rental service, but click the ‘Film and TV’ tab and you can find a few television programmes to stream. Neither site needs registration to watch free programmes.

Watching live TV
If you want free to watch live TV via the internet rather than programmes that have already been broadcast, there are two free options: the BBC's iPlayer and Zattoo. As long as you are in the UK, iPlayer offers live feeds for all BBC TV and radio channels – ­ you will see an ‘On Now’ link at the top right of each channel’s home page.

Zattoo is a legal advertising-funded service that re-broadcasts live television from 33 TV stations including BBC, ITV, Channel 4 and Five. There is a selection of other interesting foreign channels as well, such ABC News Now and Bloomberg financial TV. To use it, you need to sign up for a free account (only an email address is needed) and download the software to your computer.

For serious telly addicts and movie buffs, paid-for services offer a much wider choice. For existing Sky satellite subscribers a free choice is the Sky Player, which lets you view Sky TV news, entertainment, sports and movie channels live or on demand.

However, you do not need to have a satellite installation to subscribe; an online-only subscription costs between £15 and £41 per month depending on which package you choose. Separate player software is provided, but only one PC per household can be used, so it’s not very flexible.

Blinkbox is a pay-as-you-go movie and TV show download site, with several older movies that you can try out at no cost. Newer titles can be downloaded for around £10, or rented for around £2 ­ rentals can be downloaded, but many can also be streamed just like a TV programme. No subscription is needed, you simply pay for the films you want to watch.

Lovefilm is similar, but its online pay-as-you go service is still being tested and does not include the full movie catalogue. If you take out one of the company’s unlimited DVD rental plans, which costs from £9.78 a month, you get free online access to everything but at the moment it’s not particularly easy to browse through the movies available to stream.

Apple’s iTunes Store has a movie and TV show download section, but very little free content. Movies cost up to £11, TV shows from £1.49 upwards. Complete series can also be bought. All content has to be downloaded via the iTunes software and watched on iTunes or an iPod portable player.