An oven is an insulated box with a heating element inside. Looked at that way, is the dishwasher that much different? Sure it has spray arms for water and uses soap, but it is also insulated and has a heating element. That makes it an oven—with a few extra features thrown in.
Cooking in the dishwasher is not much different than baking; you just need to keep the food from getting soapy.
Go to http://lifehacker.com/5478670/how-to-cook-something-in-the-dishwasher to see how to make dishwasher chicken, hot dogs, or vegetables