From Springboard Net Solutions:
The software shows you both your internal and external IP addresses and it can notify you by email when they change. The program also performs DNS and Whois lookups and provides other handy IP and domain related features. This is a very useful tool if you are running web services from your computer, or are attempting to connect to your computer remotely.
Also a handy program for anyone who does a lot if whois lookups or DNS conversions. Also a great tool for anyone managing small networks at home or in the office. Load a copy on each computer and quickly see what IP address each computer is using.