What kind of question is this? Of course they accept American Express, it's Disney World. That's like asking if a popular supermarket accepts food stamps.
"VISA is the official card of the Walt Disney World Resort"
We do however also accept as valid forms of credit card payments:
Mastercard
American Express
Discover/NOVUS
Diner's Club
Carte Blanche
Disney Rewards Card
Japan Credit Bureau
We also accept bank check cards (aka debit cards) issued through VISA or Mastercard as long as no PIN number is required for use. (i.e. must work like a credit card)
In short, Disney will accept anything with money on it, they are currently figuring out a way to accept Wampum, Knuts, and the little-known Triganic Pu... Any hitchhikers fans out there.