Most temperature sensors output an analog voltage which can be read by a suitable instrument and from there to the computer. Unfortunately, the Raspberry Pi doesn't have analog voltage inputs, so by itself it won't do the job. You have a few options:
1) Digital temperature sensor. A sensor which, instead of outputing a voltage, can be queried over a bus such as I2C or SPI; the Pi can talk directly to such a sensor
2) Analog temperature sensor plus digitizer. Temperature sensor outputs a voltage, then a stand-alone ADC chip converts that to digital, and sends the information to the Pi. There's a near-infinite number of digitizer chips available; if you're starting with a Pi, take a look at http://www.adafruit.com/products/1085 , which is a nice ADC chip plus some Python code for interfacing it with the Pi.
3) Switch from the Pi to a microcontroller like an Arduino (or compatible device like a Teensy). These have voltage inputs built in, so they can talk directly to analog sensors; you can interface with LabView using the LINX library.
