TesolMax.com is a teaching specific site. Job boards and teaching related resources are their only listings.
Ohayo Sensei has a comprehensive selection of teaching positions in Japan posted, ranging from conversation schools to universities.
Japan Times Jobs has a searchable database for English teaching jobs in Japan by location. Non-English teaching jobs also.
Jobs in Japan posts many openings for teachers in Japan and covers numerous other work fields.
Smith's School of English provides English speakers the opportunity to own their own business teaching English to students in Japan.
Gaijin Cafe. A Japan portal for teaching jobs, classifieds, forums etc.
Onestopenglish.com has free resources, e-lessons, web guides, competitions and much more for English teachers in Japan.
English-to-go has pretty much everything you need. Teachers get your lesson plans now!
ESL Images provide teachers with fun, colourful and attractive ESL images and flashcards, and a large variety of ESL lesson plans.
Genki English has lots of ESL games, ESL songs and plenty of ideas to make your English lessons even better!
Tips for teachers in Japan
Set your lesson fees. Don't undervalue yourself. If you charge too little you won't earn the respect of your students. You may want to have a cancellation policy. Private students will cancel on you. You can partially solve this problem by stating from the beginning that you will charge lesson cancellation fees.
Scheduling
Keep a teaching schedule for lessons you have set, don't want to suffer those double-booking-blues!
Getting ready
As a teacher, have some sort of level check for your first meeting with a student. It serves two purposes. It makes the teacher look professional and helps determine what text you'll use. Even if your student only wants a conversation class, a level check can help you guide the conversation to topics that will help them improve in the areas where they have weaknesses.
Got a range of teaching materials? Show them to the students, it makes the teacher look even more prepared and professional.
In the lessons