Hi Jackey,
i would suggest to look into WMI, there you can easily get DHCP-Info.
WMI can be implemented in Win9x and NT4, the Runtime can be downloaded from
the web. In Win2000 it is part of the OS. For your purpose you need the WMI
SDK
For more infos, see:

general:
http://www.*-*-*.com/

SDK:
http://www.*-*-*.com/

hope it helps,

Karl Tietze [MS]