Well, their main goalscorer seems to be #18 Hwang Sun Hong. He scored their first goal against Poland, and if you watched the US-Korea game, he was the guy that got busted up and had a wrap around his head.
Choi Yong Soo is another guy for our central defenders to watch. I think he put Korea's last good chance well over the bar.
Other than those guys, what stands out is their speed and tenacity. We need to be at our one touch passing best. If we try to hold onto the ball too long, they'll be on us quick. We need to get them chasing the ball in order to try and quiet their fans and tire out their players.