That (your orignal post. I overlapped with crutschow) doesn't sound right. The way I use to measure offset voltage is echoed in this link:
**broken link removed**
You will see that a circuit is shown where the op amp is wired with a feedback resistor to the inverting input and an input resistor to the same input that is connected to ground. The ratio of Rf/Ri is the gain of this inverting configuration. The gain should be quite high to make this practical, and in the example it is 470. A typical opamp might have bias current of less than 10mV and often less than 1mV and your average voltmeter can't measure these low voltages accuratly. So applying a lot of gain means that the input offset voltage is multiplied by the gain, making it easier for you to measure. Be sure to divide your measurment by the gain to get the actual offset voltage, and as the paper shows, pay attention to the resistor on the plus input too.