The Nintendo MP3 Player is a small GBA cart-sized gadget that will allow you to listen to MP3 files stored on an SD memory card through your DS or GBA - much like the Play-Yan previously released in Japan.
For £20, you get the MP3 player which slots into the GBA, or the GBA port on your DS, with easy-to-use menus and song information displayed on the portable screen.
But beware that it doesn't come with an SD memory card - you'll need to buy one of those separately. You'll also need a way of copying your tunes onto the SD card, so if your PC or Mac doesn't take SD cards, you'll need a card reader, too.
Also bound to detract some of the excitement away from the MP3 player is that fact that it launches on the same day as the Wii, when no-one will care about anything other than getting Zelda home for a 40-hour bashing. It'll be like the quiet little boy in the corner, longing for attention.