I just ran across this article from Microsoft. It covers off a whole list of techniques for accessing files and folders. It overviews the VBA functions available and discusses a couple of libararies that you can access for more capabilities. It doesn''t go into detail on all the functions and methods, but provides links to further information on many of the functions. Some sample code is included.
If you want to work with files or the file system, you have several options available—and the best choice depends on what specifically you want to accomplish. The available options include using VBA functions, the Microsoft Scripting Runtime Object Library, the Office FileSearch object, and file system-related Windows API functions. The only things I will not cover are the Windows API functions.