Wow, I have a lot to learn yet!
So if I connect as I described (Vin (+5V) applied to one end of the PTC thermistor, while the other end of it is connected both to Analog Pin and to ground with a R2 resistence), then I can have the resistor ratio reading AnalogRead and then determine the actual Thermistor resistance =(ADC*R2)!
That is reallly cool. I am going to try it.
Then I will use Steinhart-Hart proxy to get accurate interpolation.
Thanks!