Access gets its date format from whatever's been defined in the Regional
Settings (in the Control Panel). However, before you go and alter
everyone's Regional Settings, why would you want to force them to enter
the date in a specific format? The format doesn't make any difference to
how the date's stored: it's stored as an 8 byte floating point number,
where the integer portion represents date as the number of days relative
to 30 Dec, 1899, and the decimal portion represents time as a fraction of
a day. To me, it makes absolutely no sense to force your user to use a
different format than he or she prefers.
You may find it informative to read Allen Browne's "International Dates in
Access" at
http://members.iinet.net.au/~allenbrowne/ser-36.html
or what I have in my September 2003 Access Answers column for Pinnacle
Publication's "Smart Access" newsletter. (The column and accompanying
database can be downloaded at
http://www.accessmvp.com/djsteele/SmartAccess.html)