Activating the korean input on a Mac should be pretty easy. You already have am answer. When I'm not on my computer, I go to http://people.cs.uchicago.edu/~wchae/kor/nabi.html an it works really well

Scroll down to the part that says "Activate Keyboards". If it doesn't work, let me know, and I'll see what I can do for you. :) http://tlt.its.psu.edu/suggestions/international/keyboards/mackey.html