rjkorn @ instructables.com shows us his Arduino Smoker Controller:
I had made a Sous Vide controller and thought it might work well for my smoker too. All I really had to do was change the sensor form a Dallas 18B20 to a thermocouple. The Dallas sensor tops out at about 250 degrees Fahrenheit. This particular smoker is electric but the controller will work on charcoal fired ones too. You just use the relay to run a fan and motorized damper instead of the heating element.
Smokerduino – Arduino Smoker Controller – [Link]