"May I use these images?"
Certainly, but please link back AND DO NOT HOTLINK!
"Is this Hyung-tae Kim's site? Are you Hyung-tae Kim?"
NO, this is not his site, nor am I Hyung-tae Kim. I'm just a big fan who's made a tribute to his artwork, because I think he's amazing.
"Since you say 'tribute', does this mean Hyung-tae Kim is dead?"
No, he's alive and well. He's only in his early 20's, so don't expect him to die any time soon.
"Do you know anyone/anywhere I can buy the art books from?"
Ebay member #1,
Ebay member #2,
Ebay member #3,
Ebay member #4. These are sellers who can (most of the time) ship overseas, to America, Canada, Australia, or wherever else. These are the only English-speaking sellers I know of at this moment.