Sleepy Hollow in MK, as stated above, has good iced cappucino, though it's pretty sweet. There's a place in Adventureland (behind Tiki Birds and Aladdin) that has it, too.
Epcot has two stands that sell iced coffee: there's one in Future World over near Ellen's Energy Adventure, and another in World Showcase-- turn left heading towards Mexico and it's right there. You can get real (not sweet) iced coffee there.
Don't do the dining plan, so I can't help you there.