The announcement for the service came down earlier this month, and Samsung has made the update to its Music Hub app available first on the Samsung Galaxy S III, according to a report from Fierce Mobile Content, with the app expanding to more Android devices in the future. Samsung says it’ll include 19 million songs. As a point of reference, music streaming service Spotify reportedly had a catalog of 15 million songs in June 2011.

As we heard before, Music Hub will offer both free and premium versions, although the free version won’t include streaming, unlike Spotify. Instead, it’ll be more like Apple’s iTunes: you’ll be able to listen to 30-second samples of tracks and to buy songs and albums, but that’s about it. Songs you purchase through Music Hub get saved in the cloud, so you can stream them on any device once you’ve made a purchase, and you can also download them to devices to listen locally as well.

The premium version of the app will pack a monthly subscription fee of about $12.50, and makes unlimited streaming of Samsung’s entire 19 million-song database available, as well as the ability to upload to the cloud any tracks you own that Samsung doesn’t have in its files. Earlier this month, Samsung rolled out its iTunes-like “scan-and-match” feature, which skips the uploading process by searching your computer for tracks you already own and just making Samsung’s high-quality versions of those tracks available for streaming instead.

As Fierce Mobile Content notes, Samsung’s whole service is based on another cloud music service called mSpot, which the company acquired earlier this month for $8.8 million. Music Hub’s new features are set to trickle out to other Android devices in the coming weeks, so non-Galaxy S III Android users shouldn’t have wait long for the music service.

Samsung also has said it’s considering bringing Music Hub to other operating systems, which suggests it could jump over to iOS as well. The competition there will be stiff, however – Apple already offers iTunes in the Cloud, which is pretty similar to Music Hub, and cheaper – just $24.99 per year. But iTunes doesn’t offer music streaming like Samsung does, so it’s possible the service could find an audience, especially if it has more to offer than alternatives such as Spotify.