date handling MySQL

Hi ;-)
I'm creating a simple intranet application with PHP/mySQL. In this application, I have a form: in this form there are fields with dates. In belgium, dates are stored in the form dd/mm/yyyy. MySQL requires the dates to be stored as yyyy-mm-dd. Users can change the fields manually. Some use dd/mm/yy others d/mm/yy etc... When I update my tables, the date values are all wrong of course. One solution is to make a two digit field for the days, a two digit field for the month... (and use select boxes) but this is more work URL Does anyone know how an elegant way to convert "european (belgian) dates" to the required yyyy-mm-dd ?
Thank you
Guy