I don't understand exactly what you are asking.
Are you asking about finding a mapping between existing IP addresses and
existing host names? Or are you asking about creating a list of IP
addresses not already in use and programmatically creating a list of host
names to go with each IP address?
If it's the first question, ever heard of DNS A records? If it's the second
question you might be better served to ask your question in the
microsoft.public.windows.server.scripting newsgroup. There are some people
there who are really sharp at scripting. Someone there may already have
published a script that does exactly that.