Ponyo On The Cliff By The Sea is Hayao Miyazaki's 2008 film. It sure looks magical from the trailer. It's and animated adventure centered on a 5-year-old boy and his relationship with a goldfish princess who longs to become human.
As with any Miyazaki movies, there would be a companion art book. I've found a blog, halcyon realms, that took pictures of the art book. The Ponyo art book features lots of storyboards. There's an entry on Ponyo movie stills as well.
The English version of the book doesn't seem to be out on amazon.com at time of this writing.
Here's the Ponyo trailer.
The blog also features other art books. Just check out the entries tagged with books.
The Shinkai Makoto background art book contains some of the most beautiful painting from the movies "Voices of a Distant Star" and "5 Centimeters Per Second". That is really tempting me.