Apple boss Steve Jobs has described the AppleTV as being like a ‘DVD player for the 21st Century’.

He believes – probably correctly – that in the future we will be downloading most of our music and video from the internet rather than buying physical media such as CDs and DVDs.

The AppleTV is therefore designed to act as the missing link between your computer and your TV, allowing you to download music and video onto your computer and then transmit it straight to your high-definition set.

It’s a nice idea, and in some ways the AppleTV fits the bill perfectly. However, it does have some worrying limitations – especially if your computer happens to be a PC rather than a Mac.

Where the AppleTV scores highly is in its impressive ease of use. Like all the best Apple products ‘it just works’. Or, at least, it does if you’ve got a high-definition TV and a copy of iTunes running on your computer.

On the back of the unit there are HDMI and component video connectors, which you can use to connect it to a high-definition TV. You may be able to get it to work with older sets that have component video input, but there’s no guarantee this will work and Apple won’t provide technical support for non-high-definition TVs.

If you’ve got an iPod you’ll already have iTunes installed on your computer. If not you can download it free of charge from the Apple website. It’s this use of iTunes that is simultaneously the AppleTV’s greatest strength and its greatest weakness.

Once you’ve connected the device to your television set, you can then hook it up to your home network using either its Ethernet interface or its built-in wireless capabilities. The AppleTV will then automatically sniff around on your network and locate any PC or Mac that has iTunes running on it.

You’ll need to enter a PIN number into iTunes (and, if applicable, your wireless security key) but once that’s done you can transmit any music or video that is stored in your iTunes Library straight to the AppleTV.

You can also store content direct on the AppleTV's internal 40GB hard drive.

Look at your TV screen and you’ll see a slick graphical interface that looks very similar to that of the iPod. A small, uncluttered remote control unit allows you to quickly browse through your music collection, play photo slideshows, home videos, and any music videos, films or TV programmes that you have in your iTunes library. It really is as easy as that.

The big problem, though, is the AppleTV’s dependence on iTunes. If you’ve got an iPod then you’ll probably be happy to buy your music from the iTunes Store or to rip it into iTunes straight from CD.

Unfortunately, the iTunes Store here in the UK is not currently allowed to sell any of the films or TV programs that are on sale in the US version of the store. Admittedly, this is the fault of the film companies rather than Apple itself, but it’s still a big problem for Apple as it means there’s no video content available to use with AppleTV, other than the music videos that are on sale in the UK store.

Even worse is the fact that iTunes can’t play videos sold through rival internet video services such as Sky By Broadband or Channel 4's on-demand service 4OD.

From a technical point of view we can hardly fault the AppleTV. But if Apple can’t get some decent films and TV programs onto the UK iTunes Store in the next few months then there simply won’t be much reason to buy it.