There is a date calculation error in the Contact app. When I press the People icon, then long click a person and select Edit Contact, scroll down to the birthday field. If I entered the date 11/12/1935 and select Done. the date shows in the Birthday field 11/13/2009. I select the Birthday again and the date is 11/12/1935. With some testing If I place the year on 1945 or later, the day stays 12 but if I select 1944 or earlier the day changes to 13.