From Benot Bousquet:
Happy Birthday! is a simple application for keeping track of birthdays. It reads the contents of your address book and displays birthdays that fall into configurable ranges. You can configure how long past birthdays stay on the list and how far into the future you want them listed.The actual birthday list includes the picture (if available) and name of the contact as well as relevant information pertaining to the birthday. Clicking the birthday entry displays the contact's address book information, enabling you to call (iPhone only) or e-mail him/her.Furthermore, Happy Birthday! enables you to create custom entries for people you don't necessarily want to create an address book entry for (friends' kids, for instance).*** HOW DO NOTIFICATIONS WORK? ***iOS 4:When running iOS 4, local notifications are used instead of push (remote) notifications. Every time the application launches or the list is refreshed, silent badge updates are scheduled at midnight for the next 30 days and, if enabled in the Options page, alerts are scheduled at the specified time for individual birthdays.iOS 3:Upcoming event dates are uploaded to the server every time the application launches or the list is refreshed, if an internet connection is available at the time.Every 30 minutes, the server sends a badge notification to every registered device. This notification contains a count of the current day's events.To completely disable data transmission to the server, activate Offline mode in the Settings application.