I looked up that application note 00720c.pdf for PIC as temperature sensor, ported the idea to a PIC 12F629, and added ASCII serial out at 9600 Bd to display the 'value'.
Well, the 'value' changes when that PIC is heated with a soldering iron, also when cooled with an ice-cube, so I guess I could do a compare and drive an output pin low or high if temp exceeds some value. You can program this asm, the PIC will output RS232 on pin 5. No other stuff needed. I used gpasm to assemble it, will perhaps not work on mplab, hehe.
This is just a test to see if temp sensing works. Download the asm here: ftp://panteltje.com/pub/temp.asm