The JET Program
The JET Program
The JET Program is currently suffering some financial setbacks, but it is still by far considered by the Japanese to be the best English teaching program in Japan. Having JET on your resume looks better than having taught at an English conversation school; the selection process is the strictest of the large-scale "teaching English in Japan" programs. That's not to say that getting into JET is terribly difficult; it's just a little harder than some of the others.
JET has two types of positions: teachers and CIRs. Teachers serve as assistants for Japanese native English teachers in elementary, junior, and senior high schools. CIRs generally work in city offices and help with translation and local cultural activities; they also may function as teachers when there aren't enough teachers to go around. As a result, being a CIR requires some Japanese ability, and these positions are more competitive. The salary is also higher.
Unfortunately, if your Japanese is really good, you are unlikely to be hired as a CIR. I have several friends who are fluent in Japanese and were rejected, apparently because the program coordinators did not think that my friends would be able to get anything from the program.
JET contracts are for two years, and generally you can renew for up to three more years if you're enjoying it. The worst part about JET is that you have no control over your placement; once you accept the offer, the organization will tell you where you're going.
Still, it's a great two-year program, and it's the most respected of such programs in Japan, as it is more or less run by the Japanese government.
Full disclosure: I was not on JET, but I participated in a similar, smaller-scale program.