Here's an online calculator for the Black-Scholes method method of valuing options. This is the method that companies such as Coca-Cola and The Washington Post group are using to value stock options granted to employees, and will be written off as an expense. Other companies, such as Intel (and probably my employer) are balking at doing such a thing. The stated reason is that their companies grant more options, their stock price is more volatile, and that the stock option expiration period is much longer than Black Scholes anticipated. Hence, they say, Black Scholes over values the options, and they would be expensing something that is not realistically related to the options actual value. They may be right, but the real reason they don't want to do this is because they would be reducing their reported income by incredibly large amounts (Intel would reduce theirs by around 80%) and that would just make them look bad.
In any case, I really need to read up on this method of valuing stock options. It just seems interesting. Is there an economist buried inside me?