"Users of the service are expected to be able to listen to songs they have uploaded to the service in a so-called streaming mode but won't be able to download the files themselves. That limit appears to be a bid by Google to hinder the service from being used to spread pirated music. (...) The service is unlikely to be tied to an online music store like Amazon MP3, which gives users the option of adding new songs to their music locker at the time they buy them."
If you go to http://music.google.com/music/, you'll get an error message: "We're sorry. Music Beta is currently only available in the United States," but you'll at least see Google Music's logo, borrowed from a new version of the Android music app.
Update: As Google's blog informs, "Music Beta by Google [is] a new service that lets you upload your personal music collection to the cloud for streaming to your computer and Android devices. With the new service, your music and playlists are automatically kept in sync, so if you create a new playlist on your phone, it's instantly available on your computer or tablet. You can use a feature called Instant Mix to create a playlist of songs that go well together. You can even listen to music when you're offline: we automatically store your most recently played music on your Android device and you can choose to make specific albums or playlists available when you're not connected. The service is launching in beta today to U.S. users and is available by invitation." While it's in beta, the new service is available for free. To upload your music, you can use a Windows/Mac application called Media Manager. There's also a new version of the Android music app that has a new interface and integrates with the Google Music service.
{ Thanks, Scott. }