Microsoft Sync Framework is transport agnostic platform for automatic data synchronization across different types of datasources. It can be used for occasionally connected applications (smart clients) and p2p supplications. Previously we had to either use SQL server merge replication or write own synchronization framework. And now we have a solution from Microsoft that looks very promising. There is a good documentation for this on MSDN, if you need more details or code samples you will find them there.
While playing with Visual Studio 2008, I accidentally found new item type called “Local Database Cache”. I turned out that this is really Microsoft Sync Framework integration with Visual Studio.