source: http://guide.vsnl.net.in/tcpip/columns/mp3/cc02.html

The word MP3 as technical term stands for MPEG (Moving Pictures Experts Group) audio layer 3. It is a type audio codec where audio sound is processed by significant compression from the original audio source with very little loss in sound quality. To obtain compression without the loss in quality 128 or 112 Kbit/s is used which translates into giving 1 MB file for 1 min. of sound (which means that an average CD ROM can hold 10 hrs. of music or sound). It is claimed that low-rate MP3 files sound better than Real Audio files with similar bit rates. The advantage of MP3 is that it can be broken into pieces, and each piece is still playable. The feature that makes this possible (headerless file format) also means that MP3 files can be made to stream across the net real-time (assuming the playback bitrate and speed of the Internet connection are compatible).

The only disadvantage of MP3 compression is that lots of processing power is required to encode and play files, also a sound-card is required (16-bit sound card). The hardware player/encoder/decoder is still in development & have very expensive price. Speaking of speed, it is important that you have a machine with a fair amount of resources (Pentium Class machine with about 32 MB RAM) to play MP3's and work in other applications. You can get by just listening to MP3's on a high-end Pentium mmx . However, decoding MP3's is such a CPU-intensive process that this will use nearly all of your CPU cycles and you will not be able to work in other applications in the background. But, u don't need to worry about encoding process there are lots of websites with millions of mp3 ready for download there are also Ezine on MP3 that keep tracks of this web sites.. On modern Pentium systems, this CPU usage is barely noticeable (as low as 5%) so you will be able to work quite happily while playing your MP3's at the same time.

source: http://guide.vsnl.net.in/tcpip/columns/mp3/cc02.html

So to put it simply, an MP3 is a downloadable music file. With the help of some of the links I have provided in this page you can get you and your computer jamming. Just hook the "audio out" (you know the part you have going into those cheezy desktop speakers) of your computer into a reciever instead, and you will have yourself a much greater selection of your favorite tunes right @ your finger tips. GOOD LUCK and happy hunting. Listen to music while you STILL CAN !!!