the P2P technology is not actually illegal. the downloading of files onto your computer via a P2Pis legal as long as the material is not copyright! if the material is copyright (say an artists music) then you are breeching copyright and that is illegal!

in this case of music, downloading from P2P networks is illegal and you can get in big trouble for it!

-jimmy

i would venture to say that the majority of people who use P2P networks use them for illegal purposes, mostly downloading copyrighted songs.
limewire is the perfect example of this.
so, yes- in theory, P2P is a harmless, completely legal system that is not intrinsically wrong.
but for the most part, it's used for illegal things.

probably the best places to find free MP3 downloads are the artist pages on Myspace and Purevolume.
unfortunately, not all artists offer free downloads on their pages, and you're limited by what they choose to let you download.