Just got the invite today. Apparently, plan on spending a week in Korea. There are 3 parts to the interview: Medical (apparently a big deal), Simulator, and HR. I haven't been at the helm in a couple months, so I may well be screwed. But oh the joy contemplated in parking a 330 near the old CRJs in IAD. But to answer the question:

Applied with a contract company (GAP in my case). Then Korean does monthly interviews. They fly you out and back. My favorite part is that they continue to do this after you're hired. You don't have to sweat the commute, just get to one of the 6 or so US destinations: ORD, DFW, IAD, JFK, LAS, etc. I'm not sure how the interview stretches 5 days (travel on both weekends, it seems). I also got interview instructions: Wear a suit, buy some sim time if you can. . . Has anybody actually been through the process here on the board?