It's not quite official but there's little doubt that Google will launch its Google Music service at its big I/O event later today. While the Wall Street Journal couldn't get a Google spokesman to admit it, Peter Kafka over at All Things D got Jamie Rosenberg, Director of Android Product Management, to spill the details a bit early. Google's service will essentially mimic the music locker functionality of Amazon's Cloud service , albeit without the ability to sell songs direct to consumers. Ouch. Unfortunately, Google's plans to launch a more feature-complete service were derailed when discussions with the labels broke down . According to Rosenberg, "A couple of the major labels were less focused on the innovative vision that we put forward, and more interested in an unreasonable and unsustainable set of business terms." So, rather than putting the service on hold, Google will launch its music service with the ability to store up to 20,000 of your own uploaded songs for free which you can then stream over the web to your desktop or Android phone or tablet -- any device that supports Flash (don't worry iOS users, your time will come ). Amazon's service, by comparison, offers just 5GB of free storage for about 1,200 songs stored at a mediocre bitrate. Google will also best Amazon with a feature that automatically creates playlists. Google expects to roll out the service to its US users within "weeks" with Music Beta invites going out later today to Verizon Xoom owners (others will be able to sign up at music.google.com). Keep it right here because we'll be bringing you the announcement live : And it's officially official , called "Music Beta by Google" at this point. There's a simple presentation with artists, albums, and easy playlist creation. You can manually create them, or there's a feature called "Instant Mix" that will make you a playlist based on any single song. It'll automagically pick 25 different tracks to build a "truly ingenious mix." You know, kind of like another, similarly intelligent service. All of this syncs to the cloud, which means no wires needed to download anything.But, more importantly, songs can be cached locally. You can pick any song, album, or playlist to download onto storage, at an unknown quality. It's the same pinning idea that's in the new movies feature . That and more is demonstrated in the video below.The service is launching in beta today, allowing 20,000 songs, and it'll be free -- "at least while it's in beta." Also, the updated music app is available now, which will work with any music on your phone and any phone running Android 2.2 or above. To get full-featured you can request a beta and get in line, but if you happen to be reading this from I/O you're in the beta. Congrats, you lucky bums!