Ponyo is an animated movie from arguably, if you read what the experts think, the best animator going today, Hayao Miyazaki. If you are familiar with his work (My Neighbor Totoro, Spirited Away are just a couple and I LOVE BOTH) then you can understand why so many believe there is no one better. In a world of CGI, his drawn by hand animation is that much more impressive.
The movie is about Sosuke (voiced by Frankie Jonas), a 5 year old boy who lives by the ocean in a house on a hill with his mother, Lisa (voiced by Tina Fey). One day a goldfish trapped in a jar washes ashore and Sosuke sets her free. Once he gets her in a pale he decides to call her Ponyo. But Ponyo (voiced by Yuria Nara) is not a normal goldfish. She is magical and after her father, Fujimoto (voiced by Liam Neeson), comes out from his under water home (he is a sorcerer who keeps things balanced in the ocean), Ponyo is taken back to the ocean. She wants nothing more than to become human and reunite with Sosuke but if she transforms there are great consequences that will not only alter the balance of the ocean but also the rest of the world.
The movie is beautiful in it's animation and it's story. If you think you have a great imagination, Miyazaki will make you rethink your beliefs. He creates two different worlds, one above ground and the other below, and he does it seemlessly.
Ponyo is a great movie for kids and adults will find it equally enjoyable.
I watched the DVD in English and also in Japanese (English subtitles), and if you don't mind subtitles I would recommend going with the Japanese version.
I almost forgot, Ponyo is not nominated for Best Animated Feature at this years Oscars. That's possibly the biggest snub of the year. It's ridiculous.