What you notice first about the iPod nano, of course, is its size. It's tiny, sure, but that isn't all that unusual for flash memory players. What's really impressive about the nano - and a real breakthrough for a Lilliputian MP3 player - is its screen, a bright, crisp colour display that makes navigating your tunes a breeze.

However, size does matter, so let's start with that. Take a standard business card, rip off one-quarter of it lengthwise, and what you're left with is about the size of the player. The device measures about a quarter of an inch thick - you can barely tell that you have the nano in your shirt pocket.

At £179, however, the 4GB version isn't a bargain. The 2GB nano is a dinkier £139.

The nano's screen is only slightly larger than a postage stamp, and on many MP3 players that would mean you'd never see the whole name of many of the albums or tracks you play. But the screen resolution here is high enough that it can fit as many as 27 characters across, in type that's perfectly readable.

As good as the display is, though, you shouldn't get too excited about the nano's ability to show photos. The shots I viewed looked dark and, let's face it, even good photos don't look so great when they're shrunk down to 1.5in across (the full-size iPod has a comparatively roomy 2in screen).

The other remarkable aspect of the nano is its capacity. Most flash-based players top out at 1GB, but this one is firmly in the mid-capacity range that has been the exclusive domain of players with internal hard drives. I managed to get 433 songs (encoded at anywhere from 128kbps to 192kbps) on the 2GB model I tested.

Using flash memory should make the nano more rugged and appealing to joggers, cyclists, and others who may have been reluctant to risk ruining a hard-drive player during their exertions.

Apple has taken its scroll wheel and shrunk it to tiny proportions. This initially concerned me, since I have big, clumsy thumbs, but I had no trouble at all navigating the nano. In my tests the sound was very good, too, even over the included earbuds.

Like other iPods, the nano uses a rechargeable battery that you can't replace. It ships without an AC adapter; instead, you charge it through the included cable and your USB port. Charging takes about three hours, and a single charge should last you 14 hours, according to Apple.

My chief annoyance is that the headphone jack is located at the bottom of the player. This positioning is awkward, and makes standing the player up on a table while you're listening to it impossible (though standing up something this thin is a major challenge, anyway). The nano works with existing iPod docking accessories.

The player also lacks finishing touches like a line-in for making recordings, and a means of showing its photo collection on a TV. And like all iPods, it won't play WMA files or accept music from subscription services such as Napster.

Nonetheless, if you're already an iTunes devotee - or you want a medium-size, featherweight, and fashionable MP3 player - you'll find plenty to love about the iPod nano.