The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.
One of a set of tools we're offering as a way of saying thank you for being a part of the community.
you can download it from :
http://homepages.borland.com/torry/draganddrop.htm
the homepage was moved and I can't find it
another link :
http://www.users.on.net/johnson/delphi/
you can also 'catch' the WM_DROPFILES message and handle it