How many music cloud storage apps does it take to fill an iPhone or iPod touch? We’re not sure; they roll out so often it’s hard to keep track. On Tuesday there was a noteworthy addition – Amazon Cloud Player arrived on the App Store. It didn’t get much attention from Apple, but that’s likely because the service is very much like iTunes Music Match.

If you are a U.S. subscribers to Amazon’s music service you can now access your cloud-locker to stream your collection of MP3’s to your device. You can also download music to save bandwidth when you don’t have a Wi-Fi connection or for offline listening. Cloud Player also allows you to upload your existing music collection and access your iPhone or iPod touch music library. You can create and edit playlists, but you have to buy the songs and albums, or own them already, to store them in Amazon’s corner of the sky.

Cloud Player devotees get 5GB of free stooge. Add-on storage plans start at $20 a year for 20GB. Be sure to enable automatic downloads if you want your collection to stay current – the default setting is “off.”

The only limitation to Amazon Cloud Player on iOS is that Amazon doesn’t want to give Apple a 30% take on all sales, so like their Kindle app, content must be purchased on Amazon.com and then it gets synched to your device. Look for an iPad release soon.

You can get the app here.

Sony’s Music Unlimited service, which works similarly to Spotify, Rdio, and other “all you can eat” music services, has had an Android app since June of 2011, but iOS adherents to either the free or premium online music service have been waiting for a way to stream their collection through an iPhone. As of last week, the wait is over. Basic users can play songs form their music stored in Sony’s cloud, and the full on-demand service is available for subscribers. There is also a 30-day free trial to get new users to convert.

For free you can stream, as the name suggests, endless ad-free pre-programmed genre stations, get song and artist suggestions from Sony and listen to the tracks you own. $.3.99/month opens the on-demand catalog, give access to premium channels and let’s you create and edit playlists. The app is getting lukewarm user reviews so far, and we’re disappointed it’s not a universal build, but if you use the service and have tested the app we’d love to hear your thoughts in the comments.

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