I have a start date and an end date. I want to determine if any of those
days in that range falls between two dates?

Start Date of Project
End Date of Project

if any of those days falls between another start and end date, place an x in
the field

Start Date: 9/15/09
End Date : 10/1/09

from that date range, do any of the dates fall between 8/31/09 and 9/30/09
if so mark it with an "X"