I'm asking because I'm thinking about applying to a teaching program that would send me to one of those countries.

Any general thoughts/comments about experiences, culture shock, pros/cons, whatever would be appreciated. 

There are a few people from this site who are from those places you mentioned. Hanzotherazor or whatever hes called lives in japan and hes from Aus so he might have expierienced the culture shock you might be going to have?

I would like to see south korea or japan... but not china :\

I'm pretty sure Stof is teaching in South Korea. I'd love to have gone to Japan but I went to Ethiopia instead. Wasn't a bad trade actually.

not sure about China, but I have friends who did what you want to do in S. Korea and Japan.
They loved it. You get good money that you can actually save - of course unless you spend it on the night life - which is huge in both japan and s. korea.

I was born and raised in S. Korea so I recommend Japan.

what years did you live there for if you don't mind me asking? Just wondering how things have changed over the years. Also, what did you like not like about it. I'm sure you don't want to give a life story, but some general notes would be nice.

Also, which region did you live in?

I haven't been there since 1983, but my friends go visit often.
Economically Korea is doing much better but Korea is Korea. so different than the U.S. because Korea has bunch of Koreans and they are so similar - kinda gets old.
Night life is still very fun and you can get away with so much more than the States.
Teaching English is good money but I heard some companies really make you work.
I was born and raised in Seoul and again nightlife in Seoul is really fun - I'm not drawn to it cause I'm married. haha.

My dad used to live and work in Japan so I have been there many times, it is an incredible country.

Well in South Korea all the men look like women..... I dunno if that will make it hard for you. In Japan your allowed to feel up schoolgirls on trains.. as long as they don't know who it is.

 "feel up" schoolgirls? What does that mean...?