I can't say much about WATCHING japanese DVD's in an american dvd player, but I'm sure you can find a way for a DVD-rom to play them, along with getting multi-region DVD's.
I can comment on Nausicaa though, I recently *cough*downloaded a good fansub*cough* and it is a REALLY good anime, one of the best animated movies I've ever seen. Its trying to cram a ton of information into a 2 hour film, so if you miss something, you miss it forever, so if you don't have a really good mastery of japanese, I can understand where you'll be lost for quite a while.
Also, considering that Disney is doing the localization of all of Miyazaki's works, I'm sure the disney dub of nausicaa will be VERY good, and I'll almost undoubtely pick it up, even though the film looks a little dated. I'm sure the DVD release has to up the quality quite a bit, for such a dark movie, its really hard to discern certain parts of it considering the washed out colors.
Good movie though, i definately reccommend it.