Google announced that it is opening its Music service to everyone for free for up to 20,000 songs. In addition, the company is adding a music marketplace through the Android Market, adding a catalog of millions of songs.

The company announced content partners including Universal, EMI and Sony Music. In addition to big labels, Google has also signed on with smaller, independent labels. Warner Music was not listed as a launch partner. The service launches with access to around 13 million tracks, with more to come, Google executive Zahavah Levine said at a news conference.

The company also announced that it will be offering free tracks from artists such as the Rolling Stones, Coldplay, Busta Rhymes, Shakira, Pearl Jam and the Dave Matthews Band. The Rolling Stones will be pushing six unreleased live concerts to the site from now to 2012. A single from Busta Rhymes is free to download immediately.

Users will be able to put iTunes music into their music lockers, and the Music Manager is even supposed to retain users’ playlists and ratings.

For independent artists, Google will let musicians create their own profiles for $25, upload their own music and set their own pricing. Artists will keep 70 percent of revenue generated from the service.

As for the music store, Google is curating the store using recommendations from staff members and personalized recommendations based on artists you’ve indicated that you like. Hooking in its social network, Google+, the company is also making it easy to share songs either publicly or with select groups of friends through the network’s Circles feature. Users will be able to share music from the purchasing screen — even whole albums.

The Google service will also have some exclusive content such as interviews or reviews created by “professional music geeks,” similar to what’s already available on its Google Magnifier service.

The company also announced that T-Mobile customers will soon be able to pay for their music purchases directly through their phone bills, as they currently can with purchases from the Android Market.

Google Music has been in its beta form for months, providing users with a place to upload their music and that is accessible from their computers and mobile Android devices. The revamped Android Market, music-sharing platform and music manager will all roll out to U.S. users over the next few days.

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What to expect from Google Music

Apple releases iTunes Match

Spotify releases ‘private listening’ feature