Spotify is a commercial music streaming service providing digital rights management-restricted content from record labels including Sony, EMI, Warner Music Group and Universal. Music can be browsed or searched by artist, album, genre, playlist, or record label. Paid "Premium" subscriptions remove advertisements and allow users to download music to listen offline.
Source: Spotify on Wikipedia, Official website
Spotify is currently available in the following countries: Spotify is available in Andorra, Argentina, Australia, Austria, Belgium, Bulgaria, Colombia, Cyprus, Denmark, Estonia, Finland, France, Germany, Greece, Hong Kong, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malaysia, Malta, Mexico, Monaco, Netherlands, New Zealand, Norway, the Philippines, Poland, Portugal, Spain, Singapore, Sweden, Switzerland, Taiwan, Turkey, the United Kingdom, the United States and Uruguay.
You can find up-to-date country availability details at the Spotify's Select your country page.
Spotify service requires a Flash plugin to play music.