You can find Donald at Chef Mickey's in the Contemporary Hotel, he is also featured at Restaurantsaurous (sp?) in the Animal Kingdom. Those are the only two that I know of.
my dh and i had a blast at donald's breakfastasaurus when we were on our honeymoon! it was a last minute decision for us to eat there, but we were so thrilled by the time we were done with our meal...that's one character breakfast that we plan to do again.