Most people have heard of MP3 but few have had a chance to explore this new concept in sound reproduction.

MP3 is a file compression format that allows lots of data to be packed into a very small space.

It actually stands for MPEG 1 audio layer III and is a spin-off from the DVD/motion picture industry.

MPEG stands for Moving Picture Experts Group.

The system works by carefully picking and choosing the data it saves so that any sounds inaudible to the human ear are discarded.

The end-result is a fiveminute track from a CD (which takes up about 40Mb of CD space) can be recorded as an MP3 file using about 5Mb of disc space.

It does not sound quite as good on high-quality equipment but is perfectly adequate for mobile users.

The latest mobile MP3 players are just as sophisticated as a CD player and the reproduction is virtually indistinguishable.

So where can you get MP3 files from?

MP3 files can be downloaded from a plethora of upmarket internet sites.

The best-known is www.mp3.com, which even offers a software MP3 player for your Windows, Mac or Linux computer system as a free download.

MP3 started out as a subversive and secret thing that, for a while, looked like turning the music industry on its collective head.

Accusations involving a ripping music piracy and software theft were levelled at organisations which supported the new technology.

Now the music industry has recognised the shortcomings of MP3 and very few authorised tracks by established artists are available as MP3 downloads.

The bulk of the MP3 music scene is created by new and rising artists, taking advantage of this new technology to get their music on to the street in the hope of attracting a proper recording contract from a big name publisher.

Pirated tracks can still be downloaded from certain FTP (file transfer protocol) sites and accessed via newsgroups but this is really only for the experienced internet abuser.

For those who cannot resist the urge to hack a few tracks out of their favorite CD-ROM, it is possible to download or buy an encoder/ripper programme that will give you access to the original source material.

These mini-packages are available as free downloads at www.mp3.com.

Start by "ripping" the CD file to your hard disc and then encode the tracks you want as MP3 files.

Most recent packages automate the whole process but older rippers require a little more technical expertise.

The best thing is to try one or two until you find the software you can live with.