Cool new Google Music launch for users in the US. You can store up to 20,000 of your tracks for free, and, with Universal, EMI, Sony and a 1000+ Independent music labels on board, discover and purchase millions more. You can even share a full free play of any song or album purchased in the store with your circles. Check out this fun HTML5 based tour from your Chrome browser http://music.google.com/about/tour
and the blog post is below.