No worries there. I've watched every previous Miyazaki film in Japanese and I'm going to do the same with Ponyo. Part of the reason I haven't seen it yet is because the only version they had in theaters around here was the Disney dub. And unlike most other Anime, I didn't want to just find 'alternate' means of watching it.
And I mean, I'm already not exactly a lover of dubs. I still feel that media, no matter what it is, should be viewed in its original form. But when it comes to the Disney dubs of Miyazaki's movies, I don't really find them to be that great even in comparison to other dubs, despite some people thinking they're some ofthe best dubs out there. Script content is altered and some of the voices are downright cheesy. Especially in the Porco and Laputa dubs. Which is pretty sad considering they used the same 'talent' as they used for their normal voice work (hollywood actors). But it just goes to show you, just because you're an 'actor' doesn't make you a good 'voice actor'.
Lol, oh, and Frankie Jonas (voice of Sosuke in Ponyo) does a cover of the Ponyo theme. That's another reason not to see the english dub. XD I ran out of the cinema when it started playing.
OT: Not sure if anybody has posted this yet, but 1up.com has a nice article on Ni no kuni ~ http://www.1up.com/do/newsStory?cId=3179018 ~ . :D