Lauren Ipsum by Carlos Bueno
Have just bought this for my Kindle, so can't comment on the content. I did, however, read the sample, and it's a similar setup to Spirited Away. The girl, Laurie, is confident and smart, but needs to find out about the world she's in to escape from it. Here's a quick introduction:
Have you ever heard of Userland? It's where you buy things with truly fair coins, deal in algorithms, and try to outwit logicians to gain access to the town of Symbol. There's all this and more in Lauren Ipsum, "a story about computer science and other improbable things."
The book is designed for kids aged 5-12 according to a recent WIRED article about the book and its author, Carlos Bueno.
http://compscigail.blogspot.com/2012/05/lauren-ipsum-bringing-computer-science.html