I don’t know the halachah, but it is definitely asur under secular law. And just think of the chilul HaShem if frum Jews became known as widespread willful violators.
Furthermore, most songs from most artists can be downloaded for a dollar. Are you really that poor that you can’t afford a dollar?
Besides, there is something much better with which to fill up your IPod: audio shiurim! And most of them are free.