Google Music, which just launched today, lets users add and stream up to 20K songs for free, share music with friends through tight integration with Google+, and offers users a collection of 13M tracks through the Android Market.

Apple recently released iTunes Match, its cloud-based streaming and matching service for up to 25K songs. The service costs $24.95 per year to sync music across iDevices. While the Google Music store is free to use, you can buy additional tracks in the Android Market for anywhere from $0.99 to $1.29 per song.

To upload songs from iTunes, Windows Media Player or music from folders on your computer to your Google Music library, you must first download the Music Manager.

Google Music lets users listen from the web, Android 2.2+ phones or tablets, as well as through its mobile app for Android. For users without Android devices, they can use Google's HTML5 Web app on a mobile browser. Additionally, if a user shares a song on Google+ with you, you can listen to it using the Google+ mobile app.

While Spotify offers a free version with ads, the service charges $9.99 per month in order to to sync and stream an unlimited amount of music across mobile devices, such as iOS, Android and Blackberry.

Similar to Spotify, Google Music lets you share music with friends on Google+. When a friend clicks on a song in the stream, they can listen to the full version without navigating away from Google+. Spotify, on the other hand, offers social integration with Facebook. Since f8, people have listened to more than 1.5B songs with friends on Facebook and Spotify added 4M new users.

A key difference between the social features of Spotify and Google Music is that with Spotify, you can see playlists from friends in addition to songs your friends have recently listened to directly on the platform. With Google Music, at least for now, there is no way to see friends' playlists directly on the site.

Google currently has partnership deals with big record labels such as Universal, EMI and Sony Music, in addition to 1K+ deals with independent record labels. Additionally, the Artist hub lets any artist with all of the necessary rights to upload and distribute music on the Google Music platform.

Also, be sure to check out Google's awesome tour of how to use the service.

SCREEN SHOTS AND VIDEOS

Footage from Google's "These Go to Eleven" event today.

The home page shows recent music you've added to your library.

Google Music gives you recommendations available in the Android Market based on music in your library.

Songs from Google Music appear directly in your stream.

When friends share music on Google+, you can listen to the full song for free.

Artists tab.

A 53-song playlist from iTunes took minimal time (less than five minutes) to import. Google Music also imports your play counts from iTunes but not the stars.

The Android Market offers 13M songs to purchase.

Google Music Manager lets you upload songs from iTunes and other music on your computer to Google.

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