What is apparently the next version of Android Music 3.0 is being passed around the Web today, after the software was obtained by a tech-reviews site.

A screen shot of leaked app apparently from Google that shows streaming and cache functions.

Techfrom10.com posted a note saying that it had acquired a developer version of the Android Market and on it was the music app. Techfrom10.com was down at of the time of this writing, but other sites had presumably downloaded the software and were also distributing the app.

Digital music has been watching for Google to release a streaming music service for months. Music industry sources have said that Google wants to enable users to upload their existing music libraries onto Google's servers and then access their tunes via Web-connected devices. The leaked software appears to be at least a test version of this long-rumored service.

Since Google representatives did not immediately respond to an interview request, it's hard to say with absolute certainty that the leaked app represents what Google Music will look like when it finally launches. CNET reported two weeks ago that Google had begun testing the company's music service internally.

CNET was able to obtain a copy of the app in question, which appears very similar to previous versions of Android Music. The most interesting differences, however, can be found in the settings area.

Available there are choices related to streaming music, such as "Stream music via Wi-Fi," and "Download via Wi-Fi only." There is also one called "Cache music" and a subheading reads: "temporarily store streamed music."

This would presumably allow people to store music for periods when they lose Internet connection. The question is how much music can a user cache' a trip on the subway or on an airplane

This is an important feature for consumers and the big labels. Streaming music from the Web would lose some of its attractiveness if people couldn't listen to their songs everywhere they wanted. Enabling users to cache is a must. But for the record companies, this is a sensitive area. They typically get nervous at the idea of enabling people to capture content. They have licensed the right to cache to some smaller services but none of the major players have yet to offer this.

Google has yet to secure all the licenses it needs to launch the service it has designed, music industry sources have told CNET. So, exactly what form Google Music will launch in has yet to be determined.

Last week, Amazon released its own cloud storage service that enables users to stream music from Amazon's servers.