If you're thinking about working in Japan, but are having trouble deciding what to do, then read on, and I'll make things clearer for you about the different kinds of jobs in Japan!
Most foreigners come to Japan to teach English, because they think that's the only kind of work available. A long time ago, this was actually true. Unless you spoke a really good level of Japanese (and even then it was almost impossible to secure yourself a position in a Japanese company), all foreigners were limited to teaching English at one of the thousands of English schools around Japan. Nowadays however, there are quite a few types of jobs in Japan - you just have to know where to look. You could find jobs in resorts around Japan, work in bars / restaurants, or even try out modeling if you're good looking enough!
The best place to start looking for jobs is on the internet. The best online website out there is probably Gaijinpot - they have a huge range of listings regarding all sorts of jobs in Japan. There are also a couple of great magazines which advertise a whole lot of jobs. If you're living in Tokyo, try Metropolis magazine. If you're in Kansai (Osaka etc.), the weekly Kansai flea market should have everything you need, plus some great discounts on apartments, furniture, and information on nightlife etc.!
Teaching English usually offers the best salary, but most people find it fun for the first few months, but quickly grow tired of it after that. Actually, 10 years ago, the salary was much better, and the yen much stronger in the world, so Japan was a very attractive option for English teachers worldwide to come for a year or so, and save big bucks. These days though, with the weakening yen, and the overwhelming amount of English teaching jobs available, the pay rates have gone down considerably, so it's not such an attractive option after all.
In addition, the biggest downside to teaching English is you don't get many chances to learn Japanese, and experience Japanese culture. That's why other jobs, such as resort, bar, or restaurant work are much more interesting. Working in these jobs, you're constantly surrounded by Japanese people, not foreigners, so you'll find yourself learning Japanese without even trying at all! The other benefit is you get to really see how much fun, and how interesting, kind, and heart-warming the Japanese can be. And that's the key to Japan - getting to know it's people.
So if you're just coming to Japan to make some cash, I strongly recommend against it. On the other hand, if you're interested in a unique cultural experience, in making some unforgettable friends, (and, in the case of working in ski resorts, skiing some of the finest powder in the world!) then Japan is for you.