How to display the time mesured

I try to find a way to display the time mesured on Arduino. What is the best approach to do this ?

I will press the button, and measure the time until the next button is pressed on Arduino, then I want to display it on a PC.

(Specifically, first, Press the button to light LED. Second, when someone touch the LED, press the button again. At the same time, measure the time until the next button is pressed. Then display it on a PC)

OS : Windows Vista Hardware : Arduino Duemilanove w/ ATmega328

I am new to the arduino. Any suggestion is appreciated. Thank you

Just use Serial and the serial monitor

http://arduino.cc/en/Reference/Serial