I went looking for a way to measure temperatures for cooking food (specifically smoking meats in a charcoal fired smoker) using an Arduino and couldn't find any simple & cheap plug and play solutions. Long story short, I purchased three food-grade NTC thermistors for $8/each from Thermoworks: http://www.thermoworks.com/products/low_cost/oven_temp_timer.html
(part #TW362XX) and then did my best to measure their resistance across a wide range of temperatures (approx 3.6-232.2C, or about 38-450F). Turned out to be more work then I figured and making a number of stupid mistakes along the way didn't help, but I now have what appears to be fairly well calibrated probes by using the Steinhart–Hart equation tools available from http://thermistor.sf.net
and the Thermistor4 Arduino library: http://www.arduino.cc/playground/ComponentLib/Thermistor4
Long story short, here are the Steinhart–Hart coefficients for these thermistors:
a = 1.211111230054231e-04
a = 3.762691542377820e-04
a = -1.735716635603824e-05
a = 6.538964941154940e-07
Maximal error=6.82365 at temperature=232.2
The raw data is available here: http://synfin.net/arduino/Thermoworks-Probes.xls
if anyone would like to check my work and/or assumptions.
Anyways, hopefully this helps someone else with their cooking related Arduino project!