Spotify, the popular European music service, is available in the US as of today. $5 and $10 subscriptions are available but the company is issuing free accounts by invitation only. Here is a Lifehacker suggested workaround, quite legal, for getting an "open" trial account without waiting for an invitation. The suggestion for requesting invitation got me one in a day. Note that when you do get a free account you have to put up with some ads. This or the $5 and $10 subscriptions is how the artists and publishers get paid.
Of course at the end of the day Spotify is just another music distribution service that suggests if music is cheap enough people will not steal it and share it illegally. On that front, note this article allowing ISPs to slow down or shut off your service if you share music illegally. About time. Stealing intellectual property is like stealing anything else. And just because something is on the internet does not mean you have rights to it.