Microsoft made available a test build of its Sync Framework, which can be used to take Web services and databases offline.
Microsoft Sync Framework is a comprehensive synchronization platform that enables collaboration and offline scenarios for applications, services and devices. Developers can build sync ecosystems that integrate any application, any type of data, using any protocol over any network.
The Sync Framework was developed with the view of helping users take online services offline, as well as to enable applications to be independent of the end-points that use the applications. The download is available at the Microsoft link mentioned above.