Yep, Bumbershoot is right - you can pretty much get them all over DLR, even in the hotels. One good place that has iced AND delicious blended (frozen) mochas and snacks is the little coffee/sandwich place just off of the lounge in the PPH (I forget the name of it but it's good). Of course, they also sell small bottles of orange juice for almost five bucks at that place but they sell good mocha drinks too. I would imagine you could also find them at the bakery in DCA.