It seems astonishingly naive now, but when SMS text messaging was launched five years ago, neither phone manufacturers nor networks expected it to be much of a cash cow. They reckoned without the millions of text message-mad youngsters who have turned two-finger typing into an artform and spawned a completely new language.

For many youngsters the mobile is the first accessory they throw into their bag; school playgrounds are buzzing with talk of the latest ringtones and coolest snap-on covers. And with innovations such as multimedia messaging and enhanced gaming set to take off next year, the love affair between teenagers and their mobiles is unlikely to cool.

Pay-as-you-go

The catalyst for the growth in popularity of mobiles among youngsters was the development of the pay-as-you-go phones. Before their arrival anxious parents were more cautious about issuing phones to their offspring knowing that they could quite easily rack up large bills. The pay-as-you go system, which at least gave the adults some kind of credit control, caused sales of mobiles to soar. This in turn inspired a massive growth in the popularity of text messaging, with youngsters eager to chat to each other using a system that was not only fun, but inexpensive.

Customising mobiles

In the late 90s makers realised that users wanted to stamp their individuality on phones and the concept of the snap-on cover was born. Although other makers such as Siemens offer a range of covers, it is Nokia which has developed the market in Europe and in doing so established itself as leader in the kids/youth phones. For budget-priced models like the Nokia 3310, 3330, and even the more upmarket 8210, a bewildering array of designs are available, from Stars and Stripes and Union Jacks to lurid psychedelic pinks and greens. Most covers cost between £5 and £20. Never one to miss a marketing opportunity, football clubs have also cashed in on the craze offering covers emblazoned in team colours. And now phone users can show how much they care about someone by designing a cover that features their image. For £19.99 Carphone Warehouse is offering to turn a photo of your loved one into a snap-on cover for a Nokia phone in three to five working days.

Cool ringtones

Right up until the end of the last decade most mobile phones had a rather limited selection of ringtones. The compatibility of new phones with downloadable tones, partly inspired by the success of the I-Mode system in Japan which proved hugely popular with youngsters, changed all that. Kids, of all ages could now download ringtones of all kinds, from classic movie hits such as The Great Escape to versions of the latest chart toppers. Ringtones have become so popular that even the weekly music magazine the NME publishes a ringtones chart. While Nokia was first to develop this market, most contemporary mobiles are now compatible with downloadable ringtones. It's not just downloadable ringtones that have proved a hit with the teen market. Downloadable logos, which range from football teams to images of cartoons, have enabled youngsters to further customise their phones.

Games on the mobile

Possibly the key growth area for phones next year will be games. Most models have a basic selection of rather primitive mid-80s arcade-style games stored in their memory. Nokia has increased phone-user options by offering games that can be downloaded to mobiles via the Club Nokia website (club.nokia.co.uk). Over the next 12 months those games are set to get more sophisticated, with Siemens and Motorola in addition to Nokia developing more advanced, downloadable games. The growth of Wap phones significantly increases options with users able to play sports quizzes, games such as Top Trumps and versions of hit TV quizzes such as Who Wants to be Millionaire.

Text messaging phones

Phone makers have also sought to cash in on the text messaging craze by producing models which feature a mini-keyboard enabling even faster composition of messages. Sure to be the most wanted phone for youngsters this Christmas is Nokia's new 5510. This unusually shaped model a screen between two halves of a keyboard and is ideal for text-mad youngsters. Nokia has also integrated into the phone an MP3 player with storage for over an hour of tunes and FM radio. It may provide a blueprint for how kids' phones will develop in the next few years. Phones will be a great deal more than just communication tools. They will feature games, music and maybe even photo and video facilities in one device. Next year, manufacturers will offer an enhanced form of text messaging called multimedia messaging, which enables the user to send image (taken by an integrated digital camera) and sound files as well as text. They won't be phones then, they'll be personal entertainment consoles.