It looks like the 26th will be a major day for Microsoft as Windows 8 gets released, Surface RT tablets reportedly go on sale, third-party Windows 8 Pro tablets become available, Holiday Stores open and new services launch.
That last one is the focus here with Xbox Music aka Zune Music for days of yore. As of right now, most of the core of Xbox Music looks to be just a re-brand of the current Zune offerings but Microsoft is building off of it. Some of those new features that will come with the launch is a free, ad-supported music streaming service and utilizing SkyDrive for playlists with cloud storage of music.
Those services will be available across multiple devices e.g. Xbox 360, Windows 8 PC and Windows Phone, though it is unclear just how current Windows Phone 7 devices will take advantage of them. Windows Phone 8 is well known to support cloud storage of Xbox Music and other features, but Windows Phone 7 is still hard-coded for Zune.
Speaking of, once again we’ll reiterate that if you have Zune Pass, as of now nothing is changing to your service or offerings. In fact, you will just gain some features like cloud storage.
Source: the Verge