OpenXML SDK 2.0, which you can install from
The namespaces, classes, methods and properties corresponding to this SDK is available at
http://msdn.microsoft.com/en-us/library/documentformat.openxml.presentation(office.14).aspx
The structure of the OpenXML corresponding to power point presentation is available at
http://blogs.msdn.com/brian_jones/archive/2006/04/11/573529.aspx