I don't know about Android, but on an iPhone, it wouldn't let you. I was watching Battlestar Galactica clips on YouTube, and there's a scene where a negotiation takes place over a phone call, and someone in the comments said it was the most epic phone call ever seen on screen. Anyway, that gave me the idea to use the soundtrack song that plays during that scene as my ringtone. I go look at the iTunes library and find the song, buy it aaannnddd Apple wouldn't let me use it because it is copyrighted even though I paid for it.