Calculating the number of days between dates

Please helP!!! I need a formula that will allow me to put a date in cell a2, and in cell a3 put the the number of days between 2 dates. Example.. For example (A2) shows 08/06/08, a3 to show the number of days from 08/06/08 to 08/14/2008--(a3 )14 and (a4) to shows the number of days from 08/06/08-10/05/2008 ---(a4) 60 days.

If you can advise or refer me to a site, i will greatly appreciate it.
Thanks
Ann