how do i send an automated email from excel using an if statement
 

I have a spreadsheet that has a function that manages the maintenance of
equipment. when an item goes past a certain date, a box in the same row goes
from "ok" to "due". what i am trying to setup is, when something turns from
"ok" to "due" it will send an email to a group of address's with a message
saying that the item is overdue inspection. any idea's?