The reason so many westerners go to Thailand is that there is so much opportunity to teach because the country is large and is keen to westernize. You have your choice of Bangkok if you like big cities or the north east if you like farm country. You can also teach at some of the best international schools in the word such as Patana in Bangkok or International School Eastern Seabord if you prefer being close to the ocean.
If you cannot get into any of these first tier schools you can try for some of the second tier ones which are good like St Stephens, for example, but probably don't pay as much money.
If you are a backpacker type who just wants to travel and teach to put a little food on the table, go to ajarn.com There are many private tutoring schools teaching English and if you are a native speaker you can get a job easily.
If you know of jobs please write in and share your information. If you look at an earlier post you can also volunteer in Thailand.
When you teach abroad, you are also concerned about lifestyle i.e. food, culture and people. I have worked in Thailand for a lot of years and I can assure you that you will not find more welcoming people anywhere in the world. You will always be treated well and you will not have to fear for your well being ever.
The food is also very special since it constantly mixes savory with sweet as well as other flavours and you can't beat the price if you are content to eat on the street. An amazing phenomenon happens at many intersections every night when food stalls magically appear and tables and chairs are put on the street as if they were there all day.
Thailand is also a great place to travel and you are within a few hours of whatever kind of environment you want, such as big city, beach, forest or farm land. The cost of transportation is also very low and the bus service between cities is great but bring a sweater. Although it is hot outside, they put the air conditioning on so high you can freeze to death if you do not have a coat or a blanket!