Personally, I save all dates in the database as timestamps. This enforces consistancy and allows me to use all of the built in date functions in php.
I usually allow users to enter dates via drop-down menus for month(MM), day(DD), and year(YY).
I then use "checkdate($MM, $DD, $YY)" to make sure they selected a valid combination (no Feb 31st).
I then concatenate the three variables together with slashes so that I can use that directly in my querry string to add to the database.
-- Rich Rijnders
-- Irvine, CA US