As per the first part of your question, I suggest you to take a look at the Windows SDK that ships with CVI: searching for the "Net" keyword you'll find a lot of commands and data structures to perform what you need; you'll find some sample code too. The NetShareAdd command for example is used to share a local resource.
A simpler way of doing it could be to issue a "net share" command with the appropriate parameters using system() or LaunchExecutable() command of CVI. In case you want to gather informations, you could redirect the output of the net command to a file and read back it. This is maybe not "politically correct" but it often works simpler than deeping into several dozens of help screens on SDK...
Hope this helps
Roberto