Indeed many have read about the JET Program.
They found their niche in a very interesting organization that posts native English speakers throughout Japan.
Outside of the JET Program: you can work as an Assistant Language Teacher (ALT) for your city. Apply at your city hall.
You don`t have to be a JET participant to work as an ALT in Japan. Check to see if your hometown has a sister-city relationship with a Japanese city. Often there are chances to work as an ALT through this relationship.
Some ALTs do not have a university degree. What they do have is a Japanese spouse. That is often enough if they are intending to live in their chosen city long term.
Cities and towns throughout Japan are begging locals to teach as Assistant Language Teachers in their schools. I know as I was one of them.
Teaching English in Japan: Teach on the Peace Boat
The Peace Boat is an interesting option for those who like to do volunteer work. I would love to do this one day and highly recommend it! You get a free trip around the world and teach! Where do I sign!?
When I first arrived in Japan, I worked at different language schools including ECC and the YMCA. I was satisfied with both overall, and used that knowledge to start my own schools.
Many of my friends have worked for Aeon and Geos and enjoyed their time there. I recommend these schools too if you research them and decide if the big school experience is good for you.
Pictured: The Giant Buddha of Kamakura, Buddha has been the largest student I have ever taught!