The latest sign that Google is about to launch a cloud-based music service  comes in the form of a leaked official music app created for smartphones running the Android operating system.
The blog Tech From 10 obtained a copy of the Android music player after Google pushed out a developer update for the next version of the Android Market -- Android's version of an app store.
According to reviews on Business Insider  and Download Squad  from those who have downloaded the app from Tech From 10  - which, curiously, was inaccessible at press time -- the music app includes a rating system for songs, and the option to access a cloud-based service. The cloud service option is not active on the app, but it's clearly there. It's similar to the music app discovered in the Honeycomb version of Android designed to power tablet computers. It too features a music rating system and reference to a streaming music from a cloud-based locker, and it too was not yet active.
Last week, reports surfaced that Google was testing the music service internally  to work out any kinks prior to launch.
All this activity naturally leads to speculation on timing. Even though these signs indicate Google has nearly completed the technical work on its music app, it still needs licenses to provide the content. Unless of course it takes the route Amazon did last week and simply flips the switch on a basic store-and-stream service  with more advanced features on hold until the licensing is complete.
Google's I/O developers conference is scheduled for May 10-11. Expectations are that it will focus very heavily on Android, so it's possible that Google may reveal the details of the music service even without the licenses needed to launch it.