Get ready, here comes the iPod mini - and a revolution in how we enjoy music

The size of a credit card and the price of a posh handbag, the imminent arrival of the iPod mini is set to trigger a high street music boom this summer.

Aimed at the teenage market, the compact version of Apple's hugely popular iPod digital music player will be on sale in this country in a fortnight. Experts say the iPod concept, which has already made Apple profits of £86m since its launch in 2001, is set to revolutionise the way we listen to music.

The invention has been hailed as the end of the album and the rebirth of the single, with consumers free to edit their own long-playing music combinations. The CD player, it has been suggested, is in danger of extinction within years.

The latest iPod costs £179 and can store a maximum of 1,000 tracks, a fraction of the capacity of its big brother, the original iPod which sells for £249 and is the size of a cigarette packet. Apple has sold more than three million iPods worldwide.

The John Lewis chain predicts that when the iPod mini hits the shops on 24 July, sales will rocket. More than 100,000 of the more expensive, existing iPods were sold in Britain last Christmas.

Mike Khalfey, the store's electronic buyer, said: "We've had a lot of demand [for the iPod mini] from customers coming in and asking for them, since January when they were announced in the US."

The original iPod, which tends to be bought by people over 21, has spawned a number of competitors, none of which can emulate the scale of Apple's invention. Creative Labs' Jukebox is half the size of a paperback and costs £279.

Paul Rees, editor of the monthly music magazine Q, said: "I think the interest will go on and on. In the US, Apple hasn't been able to meet the demand for the iPod mini. I think demand for these sorts of players will be like CD players a few years ago, where everyone buys them. That's the thing about any technology and music; if it gives you another way to consume songs then people will adopt it."

Sales of digital music players, which use a hard disk or computer memory to store compressed versions of songs from CDs or downloaded from the internet, have taken off in line with the growth of high-speed broadband internet connections.

Almost all music we buy now is already digitised, on CD. There, a minute of music takes up 10 megabytes using the "AIFF" encoding system. The MP3 format sacrifices some sound quality to squeeze the music into a far smaller file, requiring about 1 Mb per minute.

But songs bought online use other, incompatible formats. Apple's iTunes Music Store (iTMS) uses one called "AAC", and its rivals use Microsoft's "WMA" (for "Window Media Audio") system. All digital players except Sony's play MP3s; but songs bought from the iTMS play only on the iPod. Depending on capacity, a player can store between 60 and 10,000 songs. The best-selling model, from Apple, has a 20-gigabyte hard disk that can store 5,000 songs.

In the past three months, several rival, but legal download sites have started to try to cash in on the shift towards abandoning CDs and picking only the music you like from CDs that have become overlong and dull.

Andrew Harrison, associate editor of Word magazine, said: "All my record collection is now on my iPod. I set it to play songs at random and it feels like I've got my own personal radio station." He said that is leading to three principal changes. "It's breaking down the album: you edit it to keep just the tracks you want, instead of all the filler they put on CDs. And online buying is leading to the rebirth of the single, but also the death of the album. People are unbundling songs from albums."

Finally, he noted: "You can create playlists of particular songs, so you can create precisely the musical environment you want at any time, for the gym, for the train, for driving. And it's a social thing too: I've seen people take their iPods to a party and plug them in to play songs. I DJ'd a friend's wedding using my iPod."

Steve Levine, a producer who worked with the Clash and the Beach Boys, has written a book on "the art of downloading music" in which he forecasts that the iPod will be the "most-wanted Christmas present this year". But the iPod has its downsides: some people have been mugged when thieves have spotted them wearing the distinctive white earphones.