There are IC's available that functions as a temp sensor. All you need to do is to power it up and interface them to a PC or micro-controller to read the temperature.

Try looking at LM74 or DS7505.
I think LM74 or compatible can be found on most motherboards.

If you have the luxury of time, you can also try to request samples from IC manufacturers.
I've was able to request samples from Maxim-IC a couple of years back.
It takes a while for it to arrive but it's free (you only have to pay the local post office for about php 15 or 20).

hope this helps.