Since the first rumours of it surfaced a couple of years ago, the iPhone has been the talk of the geek community. But does that mean it's of any interest to the rest of us?

In this particular case, it is. What's so impressive about it is the design. We're not talking about the external looks, although these are very impressive.

Rather, it's the so-called user interface, which refers to the way the iPhone is actually used. No phone maker has so far come anywhere near creating a phone that's as easy to use as this one.

The most obvious feature of the iPhone is the large screen, and the resultant absence of a keypad. This belies the fact that being a phone is only one of the iPhone's features. It's also a camera, an iPod (a video iPod, in fact), a mapping device, an email and internet browser, and a personal organiser.

Now, it's true that most modern smartphones will do all of these things with ease, but that's not the impressive thing. On a normal phone, you need to scroll through menus and click buttons to get to a task. On this one, just pressing the round button at the bottom takes you back to the Home screen from anywhere else, and from there it's a single tap of the screen to any application.

The internet browser works well, showing full pages, and this is the first place the 'multi-touch' feature becomes apparent. Putting two fingers on the screen and pushing them apart zooms the page in, and the opposite motion zooms out. The same principle applies to images. In both modes, tilting the iPhone on one side switches it automatically from portrait to landscape mode. The browser can cope with multiple pages at once, and a flick of a finger switches between them.

Google Maps is included, with the ability to see satellite photographs and, more usefully, to type in, say 'pub' and get a list of all the pubs in the area. Clicking one allows you to phone it or see its web page. There's also a direct link to a customised version of Youtube, which is less useful but could come in handy for long journeys. There are also share prices and weather details on tap.

The music and video playback is the same as what you get with an 8GB iPod Touch (the slim phone includes an impressive hard disk of that size), which is to say that it's as easy to use as a standard iPod. One annoyance is the headphone connector - the supplied headphones include a microphone for making calls, but this means that the iPhone will only accept the supplied headphones, unless you shell out for an adapter.

While the phone itself works fine (it synchronises your contacts and calendar with Outlook or Apple Mail, and the on-screen keypad works fine), other shortcomings are found in the messaging area. Text messaging is quick once you get used to the on-screen keyboard, but it's not possible to text-message more than one person at once and there's no ability at all to send picture messages via MMS. While we don't consider this a great loss, some will. The 2-megapixel camera is not particularly impressive.

The phone doesn't support 3G - again, we don't consider this a problem, because 3G in the UK has been so poorly implemented. But it includes connection to The Cloud wireless hotspots, to which the phone will automatically connect when it's in range. All standard data transfer costs are included in the monthly fee.

Battery life is fair - Apple claims eight hours of talk time, but we were pleasantly surprised by being able to surf the net and watch hours of Youtube videos without much of a dent in the power meter.

The user is locked in to the iPhone for 18 months on an O2 contract, and it's not possible to use it with another provider. It's also not possible to load your own programs onto it, as with other smartphones. That's a small disappointment, but Apple will be releasing new programs for it in the future. It's certainly possible that, as with the iPod, new versions in coming months will include extra features such as satellite navigation, which might make it worth waiting for.

The iPhone probably is the world-changing device that people have been talking about - if only in that other manufacturers will have to run fast to catch up with its usability - but its main drawback is that it's extremely expensive relative to the phones that most of us already have.

The talk plan, which starts at £35 per month, for 200 minutes of talk time and unlimited data transfer, is reasonable for what it includes, but then there's the upfront £269 price of the phone itself to consider. True, it's only £70 more than the 8GB iPod Touch, but then you have to add on the 18 months at £35 each.

Were the iPhone cheaper, we'd be happy to overlook its messaging flaws, but as it is, the price isn't quite right for this remarkable phone.

Vista compatible: Yes