Formula for date minus date = number of days

Hi,

I was wondering if anyone knows how I could enter a date in one cell,
then another date in a second cell and in a third cell have
it have it so it minuses the first date from the second and calculates the
difference outputted in number of days.

Example:

04/31/08 - 04/01/08 = 30 (days)

Thanks for your time.

Dino