Prices look good, too, with individual songs costing 59p and whole albums starting at £3.
Amazon says it has signed deals with all the major labels – Universal, SonyBMG, Warners and EMI – hence the impressive claim of three million songs available as of today.
Better still, the tracks are compatible with any digital media or portable device, including the iPod.
Being DRM-free, purchased songs can be copied across to all the devices the consumer owns.
Will Amazon's service provide the first sturdy challenge to the dominance of iTunes? Let us know what you think.