There are many different places you can teach in Korea. Schools, Academies (학원, hagwon), or basic conversation classes.
Your salary will vary depending on where you teach, and how many hours you teach. In most cases you would be offered 2,500,000 won (which is around $2500) monthly with accommodation at schools or academies (yes even academies, they are huge in Korea!) for just teaching basic speaking or grammar! This is a good deal for many people because basically you can experience a different culture, travel, and earn money with minimum qualifications (BA In most cases)! However I do understand that $2500 is way below what teachers earn in the US so if you are here for the money then read on to the next paragraph.
If you've graduated from a decent college and you're interested in teaching AP level subjects then you could expect around $3000-$4000 a month. This would apply to international schools or AP/SAT hagwons. Plus, you could teach after your school hours at a secondary hagwon or tutor to earn an extra $1000 a month which would basically mean ~$5000 a month. But let me tell you, you will be physically draining yourself if you do this and end up spending more money by trying to compensate for your stress.
Since I've told you the basic price expectations from teaching in Korea (which is probably the most important aspect), I hope no one will worry about being scammed or being offered an unfair financial package.
There really isn't much to talk about in the actual teaching process. Depending on the age group and the school environment you will have good students and bad students. I find most Korean students to be well behaved... Except there are times when elementary students are difficult to handle.
My tip is, enjoy the students you have, the people around you, the country, the culture, the food, and be enthusiastic about who you are. If your students see that you are actually trying to teach them something, they will appreciate it and respond with a positive attitude.
Here are couple interesting interviews of teachers who've been in Korea: