You couls also try to encode your music in to the ogg vorbis format. The files will then have the extension *.ogg.

Ogg Vorbis is better than the mp3-format. There are three reasons for this:

Convinient file size.
Better sound quality.
Ogg Vorbis is free. The source code is free, therefore it is difficult to stop Ogg Vorbis or implement licens fees.

See more at www.vorbis.com. Where you also can download software.