Just to through this out there, there is a program ran through Oregon high schools called the Oregon Intercultural Association Japan Homestay. I have been on the trip twice.
Each summer about 40 kids from Oregon HS (and some college students, the only real requirement is that you're a student in HS or College) go to Japan and spend 3 - 4 weeks living with host families all around Japan.
It is not an academic program, but I definitely learned a lot from living with Japanese families. It only costs around 2,500 dollars for round-trip airfare, JR Rail pass (this pass allows you to take any JR train during the time you have it, it pays for itself by about the second trip on the Bullet Train), 3 - 4 weeks of housing (with familes, who will provide meals like breakfast and dinner) and trips to places like Kyoto and Hiroshima.
The program is headed by Dr. Katsu Ozawa, one of the nicest and most intelligent person I know. He is a faculty member at George Fox, but I don't exactly how to get into contact with him now (he is usually out of the country).
If this sounds interesting and you attend a high school around Beaverton or Eugene, ask around and I'm sure the contact information will materialize.