FolderShare is a Windows Live Service that allows people to share their files with their friends, family & co-workers, and synchronize files across multiple devices. People can also access their files from anywhere on the web.
Looks cool. Sure your device (computer) has to stay up and connected for the P2P network share to work, but looks like a good solution for the family.
Source : LiveSide.net
Official site : www.foldershare.com/