There are various places to get them depending on whether you want sweet, spicy, stuffed ... most places have 1 or 2 varieties. I've heard of plain, cream-cheese stuffed, spicy cheese stuffed, apple cinnamon, and I forget what else.
MK: Scuttle's (Fantasyland), Lunching Pad (Tomorrowland)
Epcot: Fife & Drum (USA), Sommerfest (Germany)
Studios: Anaheim Produce, Herbie's, Min & Bill's,
AK: Harambe Fruit Market, Safari Pretzel (obviously)
If you want details on types and sweet vs. savory, menus are on allears.net or wdwinfo.com