MP3 is setting the new standard for MPEG audio compression. Using this technology you can get a compression rate of 1:10..12. So a average 3min song would take up 3meg and would play at CD QUALITY.
Using MP3 compression you can fit around 200 songs on one CD! This could be a new form of music distribution!
First you will need a player so you had better look here, Another good place to start is here.
MuseArc - Another MP3 player (currently beta)