Just got back from Niseko in Japan. The resort and ski school is run by Aussies so no language problems, plenty of nursery slopes for beginners, and you can buy/rent whatever you need there. Two thumbs up!!
Just got back from Club Med Sahoro in Hokkaido (http://www.clubmed.com.hk). A bit pricier than its neighbours, but being all inclusive lets you focus you attention on ski lessons, and not "oh where should we eat tonight and it's snowing hard".
Ski lessons are carefully graded, and they won't let you advance to the next level unless you have demonstrated your ability (my husband and a friend got bumped down, ha ha). Half of the instructors are from Australia, Canada, US, NZ. The other half are Japanese, but speak relatively good English when compared to the other resorts. The kids lessons are very well organized too.