Hi guys, I'm traveling to London next 23. I will be arriving on christmas (because I'm from Buenos Aires and the flight connects in New York). Thanks to that connection I have a free day in the Big Apple (which will be the 24). As title says, I'd like to buy a 4S. What should I do? Just go to the Apple Store and try luck? Being the day before Christmas I think It won't be easy, I read something about making a reservation a day before.