Download this and unzip into your Windows directory.
It's a few different utilities that I like. To use host.exe, just go to the prompt and type "host somedomain.com" and it will list all IP addresses. It can also do reverse lookups, just type "host 12.34.56.78" and it will return the name, if available. There's also a handy finger and whois utility in that zip.
Edit: Is this what you're looking for? After re-reading your message, perhaps you're looking for a utility that probes an entire subnet and finds all devices. If that's what you're looking for, go to 
TUCOWS and browse around, there should be something you could use.