@OneSalient, I doubt when Trent released the album under the BY-NC-SA CC licenses, that he was saying "steal the album from a torrent site". I'm fairly certain those licenses were there so people could use them in creative works for free and not have to pay outrageous sums of money to license it for filmwork and whatnot that one usually has to pay.
Last.fm should have all the Ghosts tracks available as free mp3 downloads. Permission from NIN is not needed since the music has been licensed under a Creative Commons Attribution Non-Commercial Share Alike license. I was able to download the entire album (36 tracks) in both .mp3 and .flac formats at a bitorrent site. This was not illegal as the CC license allows it.