Temperature at a distance

I saw a thread for this already kind of, but the distance is way different.

If I am combining two chemicals and need to keep them at that temperature for x amount of time before its time to do the next step, is this appropriate? Basically I'd measure for when it hits a certain temperature and then have it notify me when its been at that temperature for x minutes. I could put it very close to the fluid.

Appropriate as in easy to hack into an Arduino (something I've never done before)

Second question is, the only good electronics site I know is sparkfun, can anyone suggest other reliable sites?

How about the related product mentioned on that page:
Infrared Thermometer - MLX90614

Cheaper, and no need to hack the device to get readings

Your powers of observation are impeccable. Perhaps I should open my eyes when looking at the page haha