I actually already have an arduino-flashed ATMega chip. I could plop it in one of my micro-breadboards, but I think that besides 5v DC, I need a crystal and a cap or an oscillator or something else. Maybe I'll find that info on one of those sites.
As for the temperature sensor, it seems they've already invented a custom solution for my application. I believe they are calling them "thermistors". Amazing what you can buy off the shelf these days!~