How do I use a KTY 81-220 temperature sensor in arduino?

Hey guys, I have two temperature sensors lying around here and I was planning on using them for a mood lamp that corresponds to the current temperature. Well, here is the problem: The temperature sensors only have two instead of the usual three leads. There is a third is a third pin in the middle but it is to short to connect anything. The data sheet says, that no voltage is to be applied to it. http://www.reichelt.de/Sensoren/KTY-81-220/3//index.html?ACTION=3&GROUPID=3190&ARTICLE=9599&OFFSET=16&

The KTY81-xxx is a thermistor (Rt) with a positive temperature coefficient of resistance. See the datasheet for calibration data.. You may wire it as a part of a bridge, or a part of a simple voltage divider. Search for "bridge thermistor"

See http://playground.arduino.cc/ComponentLib/Thermistor

Since yours is a 2K thermistor you would use it with a 2K resistor; example above shows a 10K resistor.

Thanks a lot! It really drove me nuts :)