SEOmoz has created a tool that allows you to enter an IP and to locate it on Google Maps. The application uses Ajax so it will display the map as you type (it's useful to test Class C IP ranges).
So next time you find a strange IP in your stats, or when you want to find the address of someone and you know only the IP, use this mashup. The results are not extremely accurate as there are many ways to hide the IP and many machines are behind a NAT.
Note: I'll be gone in a short vacation, but that doesn't mean I won't be around. Starting from tomorrow TomHTML from Zorgloob will keep you company. He asked me to tell you he's not fluent in English, but I'm not either.