In a near future it will perhaps not be possible to download and copy MP3 for free. The company that owns the MP3 concept is going to put in the so called DRM (Digital Rights Management) for MP3. So MP3 will be very restricted for us who are the consumers.

I think it is better to use OGG Vorbis .

Ogg vorbis files have a better quality of sound compared with MP3. And no restrictions will be put in for OGG Vorbis, so OGG Vorbis is more safe and have a brighter future.