The 2007 Microsoft Office System Open XML specification, recently approved by the ECMA International standards organization, includes a new file packaging technology. An underlying component of this standard is Open Packaging Conventions (OPC).
OPC provides a container technology you can use without having to code your own custom binary container files. It supports a number of enhanced features, and because they adhere to an open standard, package-based files can be accessed through high-level services such as workflow applications and virus scanners.
In the August issue of MSDN Magazine, Jack Davis and Andrey Shur take you on a tour of the new standard, showing how to use .NET Framework 3.0 APIs to organize your application’s storage of multiple data streams in a single portable package.
Don't forget to explore the code online, too.