Additionally, Spotify for Linux is currently available to just their Spotify Premium subscribers. There is a free version of Spotify for Microsoft Windows and Mac OS X, which relies upon in-application advertisements for its revenue. Spotify developers haven't yet found a reliable way to display these ads on Linux, so the free Linux version hasn't yet been released. Beyond that, the Spotify P2P service still isn't available to those within the United States or a number of other countries, but is available to those within the United Kingdom, Norway, Sweden, and select other European countries. Needless to say, the official Spotify Linux client is not open-source software.
Those interested in trying out Spotify for Linux if you are one of their premium subscribers can find instructions from the Spotify Previews area. This initial build is only packaged and made available for Ubuntu 10.04 / Debian Squeeze.