http://alphavss.codeplex.com
Using the Windows Volume Shadow Copy Service (VSS) on the .NET platform in C# (or VB) is somewhat problematic to say the least.
To further complicate things there are actually multiple versions of VSS depending on what version of Microsoft Windows you are running and for which platform it is targeted. Most notably Windows XP and Windows Server 2003 requires compiling and linking your application against the Shadow Copy Service SDK 7.2, with separate header files and libraries depending on the version of Windows you are targeting. From Windows Vista and onwards things are simpler though with all the functionality available in the standard Windows SDK.