First post about one of my iPhone App: MyFriendsMap.
This is a kind of social app that will parse the address book of your iPhone (no data is sent to any server) and retrieve all the addresses of each of your contacts. After the DB of the app has been populated with the addresses, they will be displayed on a map so you know which of your contacts is close to your current position.
The application has as well a feature that will help you by showing you the direction of any address of your contacts. Simply select one address and you will get the distance and heading to that address.