I looked into going to the KD 2 years ago (still planning on going if I can ever get the money again lol. Decided to buy a horse trailer instead :(
Anywho... Try these: DerbyBox.com - Kentucky Derby Tickets Kentucky Derby Tickets | 2011 Derby Tickets | Kentucky Derby Travel Packages | Churchill Downs Tickets
Just a warning, the KD is expensive! I think like $300 is the cheapest for ONE person! & those are crummy seats. The prices go up to $5000 a person I think lol. Nuts.
(Infield is really cheap, though - I think! Though, again, not the best spot...)