Kirk Ouimet has put together some really good web tools at YouGetSignal.com.
The tools include:
- Port Forwarding Tester: find open ports on your connection
- Network Location Tool: locate a network using Google Maps
- Visual Trace Route Tool: plot the route to network address
- Phone Number Geolocator: figure out whos calling
- Reverse IP Domain Check: find other sites on a web server
- WHOIS Lookup Tool: check to see if a domain name is available
