Studio Ghibli DVDs are all coming out one by one in Japan. Castle of Cagliostro, Grave of Fireflies (out in US), My Neighbors Yamadas, Kiki's Delivery Service are out with Totoro coming out in September. The rest are all set to be released next year. They all have English subtitle and some of them have English dub as well. They cost around $30-45US and you can get them at amotokyo or cdjapan.

Cagliostro and Kiki (possibly all future releases) have a neat second disc with the entire film in key frame/story board form synched to the audio.