As mentioned by others, there have been nurmerous posts, somestime quite heated debates, over this issue.
One person went to Disney and asked for their official response...no electric appliances of any kind are to be used in standard hotels unless they are provided by WDW. This is for safety(fire hazard) reasons.
Personally, I would not want to be staying in a hotel room, paying a pretty $$$, only to have to smell other people's cooking.
There are many other ways to save money, cooking in your room is just right.