Hi,
If you don't have a friend who speaks Japanese, you can use a "deputy service". They are generally used for buying anime cels on Yahoo Japan now, but many of them will allow you to buy other items too, as long as they're not as large as a refigerator. Two good ones are:
www.animechaos.com (I use this one)
www.rinkya.com
Both provide search engines, of sorts, for browsing yahoo Japan. For looking for headphones, what I do is go to this link:
http://www.animechaos.com/deputy/yhjtranslatedlist.htm
Then click on the "Appliances, AV, Cameras" category. Next, in the upper-left-most textbox, enter ATH-W100 and click the gray button next to it. There you go, 2 W100's right off the bat! You can use a translator like babelfish to try to get the gist of what the seller is saying, but, well, the translated text can often be pretty hilariously unreadable.
Just watch out for the deputy fees and know beforehand what you'll be paying, they can catch me off gaurd sometimes! Every now and then they'll have a sale on their fees, if you can wait.
Heh, I was looking for W100's too a couple months ago, but now that I've got HD650s I lost the craving
Good luck!
