Just for clarity, thermistors and thermocouples are different. Thermistors work by utilizing an electrical resistance that changes with temperature. Thermocouples (e.g., Type K or Type B), work by generating a voltage difference between two dissimilar metals that changes with temperature. The LM34 that Electrotech mentions is an integrated circuit sensor that outputs a voltage that varies with temperature, again utilizing resistance change of the components of the IC. Each type of sensor has a temperature range where it works best and is the most linear and repeatable. The IC sensors have three leads instead of two since they need a supply voltage to work.
OK, back to smoking meat!