Actually there were 200 lottery spots for the 2003 Kona Ironman, I was there as my buddy was selected in the lottery. If you are picked in the lottery, you have something like 6 months or so to simply complete a half iron man. Then you can enter the World Championships with your lottery spot.
As far as straight up qualifying, I think you have to get 1st or 2nd in your age group at a qualifying race, of which there are several, I will email him more about it and get the info up on here for you all.