Tens of millions of children are using tablet apps in 2012: games, book-apps, educational apps and more. Now Amazon is looking to capitalise with the launch of a subscription-based children’s entertainment service for its Kindle Fire devices.

It’s called Kindle FreeTime Unlimited, is aimed at 3-8 year-old children, and will cost $4.99 a month per child or $9.99 per family, although members of the Amazon Prime service will pay $2.99 and $6.99 respectively.

Amazon has a stellar lineup of content for the service too. Games include Disney’s Where’s My Water and Where’s My Perry, Fruit Ninja Puss N’ Boots and Cut the Rope; Books include titles from brands like Shrek, Kung Fu Panda, Looney Tunes, Thomas & Friends and Superman; plus TV shows and films like Bob the Builder, Fireman Sam, Sesame Street, SpongeBob SquarePants and Yo Gabba Gabba.

People who buy Amazon’s Kindle Fire and Kindle Fire HD tablets will get one month of the service for free, with the service due to pop up on existing devices as an over-the-air update in the coming weeks.

Amazon stresses that all in-app purchases, ads and social networking features have been removed from apps that are part of the service, with the company screening all content for its suitability for children. A key point: once subscribed, kids will be able to choose their own downloads, assuming parents trust Amazon’s curation.

For now, this appears to be US-only, but there is clearly scope for it to roll out internationally, following the path trodden by the Kindle Fire devices.