SharpCast

Sharpcast Photos syncs the photos you add and edits you make on your desktop, web, and mobile phone in real time. The new version now allows you to collaboratively edit your photos and galleries in real time. Collaboration consists of the ability to share files and read/write privileges in public or private folders along with real time chat built into the client.
They currently have a broader file syncing application, Hummingbird, in the works. Hummingbird will handle syncing for all file types. It is essentially the same animal as the photo sharing application, but with fewer bells and whistles. Hummingbird will note and push your updates to your other platforms, but won’t carry out the same real-time updates of the photo product. To avoid the problem of two people making concurrent edits to a file, they will have to be saved, and then opened elsewhere to make changes. While Microsoft Word does support editing concurrency, Hummingbird does not currently support it.