Amazon Cloud Player, Google Music, Slacker Radio, Rdio, and a host of other similar services are set to face serious competition in the United States as Spotify preps for landing. After years of hopes and high expectations, Spotify’s website is now taking email addresses for invitations. Promising “any track, any time, anywhere” and for “free” we’re not totally sure what lies ahead for US fans although we figure it won’t be all that different from other parts of the world. If so, look for $10 per month for Premium access and unlimited streaming across your Android (and other, less cool) devices. As far as the “free” stuff goes, we would expect limited playback hours, advertisements, and lower audio quality.