EDP doesn't mean you apply any earlier (well, maybe a couple months earlier, but in the same application cycle that normal applicants apply in). You only apply to one school, but that school makes a decision on you by Oct. 15. After Oct 15, you can apply to as many schools as you want. EDP is great if you are absolutely positive you want to go to a specific school and you feel you are super-qualified. It's not so great b/c if you are not accepted then your application is delayed at other schools.
If I am not accepted this year, I plan on applying EDP to my first-choice school for 2004. After having gone through the process once, I know that this school would be the absolute best for me. But I wouldn't have known that w/out applying to 18 schools this year and doing large amounts of research about those schools. I know that applying EDP is a risking my chances at other schools, but I want to go to this one school so badly that it's a risk I'm willing to take.