MacRumors has found references to a new 'Find My Friends' feature in iOS 4.3.
Some further digging into the newly released iOS 4.3 developer build has revealed settings for a new feature called "Find My Friends". The strings are associated with the Settings app and is related to "MobileMe". The obvious interpretation is that Apple may be looking to offer a location-based friend-finding service like Loopt and Google Latitude.
The new iOS 4.3 beta seems to providing many tidbits of interest. We'll keep you up to date as new findings occur.