If you own an Apple TV or any AirPlay-capable receiver, music can be beamed from any iOS device, Mac or Windows computer with iTunes to your living room setup with the tap of the virtual AirPlay button.
Meanwhile, iTunes Match is Apple's $25/year service that provides cloud access for up to 25,000 of your songs on your iOS/OS X/Windows devices via music populated in the iTunes Store. If you live in an area with a good cellular signal and have an iOS device with limited storage, iTunes Match is a good buy.
The just-announced iTunes Radio will have more than 200 streaming radio stations and, as with Pandora, you'll be able to build your own radio stations based on your musical preferences. It will be free and ad-supported, although anyone who subscribes to the iTunes Match service ($24.99/year) will get it ad-free. It will integrate with iTunes, so that you can buy any track in iTunes that you're listening to in iiTunes Radio.
The question is: Will that be enough to fend off the competition, notably Pandora and Spotify? We won't know until its availability in the fall. But just having Apple's backing makes it an instant contender.
In addition to offering albums and individual tracks for purchase, the Google Play Music interface allows you to upload your existing music collection and then stream it from Google's servers to any PC or mobile device. Any music connected to your account can also be "pinned" to a device for offline consumption.
As of May, Google also offers an on-demand streaming service called Google Play Music All Access; it provides unlimited streaming from Google's music library for $9.99/month. Songs from the service can be played on any device, be it a computer, smartphone or tablet. The All Access service includes an option for custom song- or artist-based "radio stations" in the style of Pandora, with no limit on the number of songs you want to skip.
At this point, Google Play's library of content is generally quite good. The store used to be rather limited in its music and movie offerings, but deals inked with Warner Music Group, 20th Century Fox and Time last fall rounded out the once-lacking selection.
When you think of Microsoft, music doesn't come to mind. Its Zune digital music player was a well-publicized flop, and it doesn't have a cloud-based music player like the Amazon Cloud Player or Google Play Music. Still, with its Xbox Music service for Windows 8, Windows Phone and Xbox 360, Microsoft has made an attempt to knit together a serious music ecosystem, and it's a good one. (Windows XP, Windows Vista, Windows 7 and Windows Phone 7 users can only access the older Zune software music service.)
The Xbox Music app is built into Windows 8 and Windows Phone 8 and, of course, into the Xbox 360. But despite the app's name, you don't need an Xbox 360 to use it. It's yet one more example of Microsoft's confusing product naming.
There are two components to Xbox Music. One is an a la carte service that lets you buy tracks or albums individually. Its music selection is comprehensive and superb; Microsoft claims it has 18 million tracks in the U.S. from which to choose.