So if I enter 05/03/2005 is that May 3, 2005 or March 5, 2005; and how does
Access tell the difference?
You need to understand how Access interprets dates - it will use the short
date format as set in the Regional Settings of Control Panel. And that may
be different on different computers. Although you could change everyone's
computer, you really shouldn't change their preferences.
For a date, you are better off not having an input mask as it just slows
down data entry. You can enter mm/dd or dd/mm (depending on your computer
settings) and Access will assume the current year.
You should set a format that is unambiguous, so that the user can tell
immediately how Access interpreted their entry.
dd/mmm/yyyy is suggested
More information on dealing with dates at
http://www.allenbrowne.com/ser-36.html