Lime wire
Qtrax
im looking for it right now...=.= Zippyshare.com
itunes
itunes
4chan.org the rapidshares section.
Frostwire
clubcreate.com
1. beemp3
i mesh is the best for downloading and listening the good quality music
megatorrentz.com
Not if it is purchased or if it is provided by a licensed site. Programs like iTunes allow you to pay for downloading your music... that is legal.
Downloading music for personal use should not be illegal, but it usually depends where you downloaded from or what site