Shopping at Amazon Japan and having books shipped directly (anywhere in the world) is much easier than you think. There is so much assistance in English. Here's how to do it: Open the website Amazon Japan. Find the button on the top right, click: Shop in English. This page will open:
Read the FAQS for shipping rates, countries shipped to, item restrictions, customs duties, etc.
The search bar is now top center, you can search all departments or use the pull-down menu to search for DVDS or foreign books, etc. Since you probably want to buy Japanese books the easiest way to do that is to enter the ISBN number. You can find them on other people's blogs, flickr groups etc.
Here I've entered an ISBN number for this book. I like the look of it so I think I will buy it. At this point I will open a new window on my computer to check out the exchange rate. I think xe.com is pretty popular. I click Add to Shopping Cart. If you're not sure later you can remove it.
Now the book is in my shopping cart (click top left to view in English) and it's time to pay. You can also keep shopping. Amazon has made some recommendations that you can click on to view or simply add to the cart. I am just going to buy the one book today (it's tempting though isn't it?). Click Proceed to Checkout.
Next we're asked to enter a shipping/billing address. It's all in English (phew!) but you need to click top left to enter an International address (i.e. outside of Japan).
Next up is payment. As an International customer you'll have to pay by credit card. Payment at a convenience store is also an option if you know someone in Japan who can do that for you I guess.
Press continue and you are almost there! One of the final pages is this order confirmation. At this point Amazon has calculated the shipping charges based on your location and the number of items you have ordered. You can see in the center a button to click for more information. If this all checks out then click Place Order - the final confirmation (are you sure?) Your credit card will be charged and your books on their way! You'll get an email confirmation, usually within 24 hours. I'm not sure what happened next since I didn't really want to have this book sent to me in New Zealand. I'm sure it's just a thanks for your order page.
I hope this helps. I have a few books that I have reviewed in my side margin. My Amazon store. If you need help searching or want me to look up ISBN numbers I can do that. Happy Shopping!