Teaching in Japan?

How difficult is it for an American to be able to teach English in the Japanese school system? I was thinking of teaching English in kindergarten maybe. How difficult is this to do though? I've heard by some it's easy and others have said it's very hard. Does anyone know where I could find out ? Thanks!
=Rika=

Your question is not specific enough.

Do you mean become an Actual teacher hired by the school administration. Or do you mean become an "ALT" Assistant language teacher, one who is supposed to "assist" the main teacher, but you often end up doing classes your self.

The later is somewhat easier. The former requires you to actually become a teacher.

if you want to be a kindergarten teacher I don't think that you need any special certificates. I teach at an international preschool, kids ranging from 3-6 with no sort of teaching qualifications. I teach my own classes in English. I only warn you that teaching on your own in a kindergarten is really stressful, and a lot of responsibility. Japanese kids are more bratty than American kids...no offense to you Japanese kids. It's this amae thing they have working for them, Japanese kids are way too spoiled (this is what I have witnessed as well as what other teachers have told me). No worries though, if you like kids, Japanese kids can be put into shape like any other kids, they might just take a little more time.

Governmental education begins at kindergarden level up, so preschool level might not be as regulated. But if you have a school that is under the watchful eyes of the Government (eg Boards of Educations) to become and actual real deal teacher (not a ALT or dispatched through a company or JET), then those teachers (eg the Japanese teachers) usually need some qualification.

What about high school? If I wanted to teach English in a high school? And is becoming a certified teacher--is that difficult ? I really have no idea what I'm getting myself into here. :D So I just wanted to know if anyone has any experience with that. Thanks for the responses by the way! :)
=Rika=

There are many thousands of foreigners teaching Japanese at schools in Japan, You need to look at the dedicated ESL websites which have loads of information and also job offers. Don't forget to check out the FAQs first.
Here are some:

http://forums.eslcafe.com/job/viewforum.php?f=11

http://eltworld.net/forums/viewforum.php?f=35

http://www.ohayosensei.com/

And also look into the Jet Progam, which is one of the most popular for working in schools in Japan

http://www.jetprogramme.org/

If you Google you will also find lots of other sites and blogs with people's experiences. This question has also been answered a lot on this site, so have a look down the page in the living section for some more info.

Bear in mind that you will need a full bachelor's degree to be eligible for a working visa in Japan.