9to5Mac has been disecting the beta release of iOS 4.3 and according to their findings, a folder is present that references MediaStream. They speculate that this folder is reserved and only to be activated once the iPhone 5 has been released. At which point the MediaStream feature will go live, allowing users to share pictures with friends instantly and automatically. 9to5Mac reports that the service seems to be utilizing MobileMe.
Another feature that was uncovered is Find My Friends. This service will allow you to quickly pinpoint all your iPhone wielding friends easily and accurately using GPS and a maps service of some sort, probably Google Maps.

