I believe you need to find a dll file that will allow you to do PORT IO on an XP (or 2000) system. You then need to use DllImport() (from the System namespace? I'm not sure, look it up) to be able to use the dll functions. I haven't done this for a couple of years so I could be mistaken. Google DllImport and .net and visual basic to find some stuff on it. I don't remember it being too hard to do.
Microsoft only shows you how to open the Serial and Parallel ports as files to read and write to. It does not allow access to the Status Port and Control Ports bits. It also requires that you still interface to a dll, namely the kernel32.dll. There is a reason people write low-level IO code that changes permission mappings to allow port IO at the bit level.