Dates quickly shows the age, astrological sign, and Chinese Zodiac for contacts in the iPhone or iPod Touch Contacts database. Dates also conveniently displays a list of pending future dates and dates that have recently occurred.
If no people show up in the people picking list at all, or if a person shows up but when you select them nothing appears but their name and picture, then nobody has a date assigned to them. Try following the instructions below for assigning a date to a contact.
Use the regular iPhone Contacts app to edit the person and assign a birthday or other date. To assign a date, after entering edit mode, scroll to the bottom of the list and choose 'Add Field'. From the items that appear next, select 'Birthday' or 'Date'.