Mike from EngineersGarage sent us this link. He used the LM35 from National Semiconductors to make a temperature meter. This chip provides a voltage output according to the temperature on its shell, so he used the Intersil's ADC0804 analog to digital converter to get a digital value out of it. He used the Atmel 89C51 microcontroller to interface the ADC with the standard 16X2 LCD and display the temperature.
The complete worklog along with schematics can be found in this page. You can download the code only if you are a site member (i don;t really understand the reason why...).