After all the trouble, I can't recommend Apples reservation system for non locals. You can't predict how long it will take, and worse, you have to pick it up one day after the confirmation E-Mail
From my experience, just check availability in the nearest Best Buy store and go for it. Good Luck!
I'll be there for 16 days, so it won't be a problem - I'll have access to wifi at my villa (on my new iPhone 4, hopefully - but on PC too). It won't be a problem for me to respond when I get the email.
What I think I might do is get it when I get to Boston on NYC, if there are any available, but if not, I'll reserve one as soon as I arrive in Florida - which should give them 15 days to get me one.