Rdio is an ad-free music subscription service that is available as a website and has iPhone, iPod Touch, iPad, Android, BlackBerry, and Windows Phone applications.
Rdio was created by Skype/KaZaa founders Niklas Zennström and Janus Friis. Rdio is now available for free without hearing a single ad. A meter will appear at the top of Rdio that shows you how much free music you have each month. You can create an account with your Facebook account. No application downloads or credit cards are required.