NTC 2k2 is a resistor, which significantly changes its resistance with temperature (R decreases as T increases). 2k2 at room temperature (25C), around the value of the most widely used temperature sensors in the automotive industry (GM, Honda, etc...). Choose airdenfactor_2200_256 during firmware upload (or 2063_256 if you want slightly lower reading) .
They fall to in the 100 Ohm range at 100C, and even lower at higher Temp. Usable for about 150C. Above 150C (EGT, head-T of hot engines), the thermocouple is used (which is much more costly and harder to measure, but more linear) for measuring temperature.
The MAT and CLT sensors of most cars are this component packaged for easy mounting to a particular engine (usually threaded). This can be mounted with epoxy glue.
Package:

• Axial: now OUT OF STOCK, supplier says available by end of January 2011 the more expensive NTC looks like a glass diode, legs at the opposite end (axial package): can be mounted with better vibration resistance. Extremely fast response
• the radial package has legs on the same side