Google's Jamie Rosenberg, director of digital content for Android, said Google Music is an expansion of Google Music Beta, introduced earlier this year, making it a "full end-to-end service."
"It's about the cloud, about the Web and about mobile," he said.
Google Music, accessible via music.google.com, is open to everyone in the U.S. now on the Web and will roll out to mobile users in the coming days. Users can store and stream up to 20,000 songs in the Google cloud for free, and add any selections they don't have by buying them from the Google Music store.
Google Music will allow users to share songs with friends, who will be able to play that song in its entirety once.
Google said it has sealed deals with more than 1,000 music labels, including Universal Music Group, Sony Music Entertainment, and EMI, as well as indie labels, like those from Merlin. In all, Google promised access to 13 million tracks, 8 million of which are available now.