Here are a few good sites for "researching" an IP address.
IP2Location offers a 20 free look-ups per IP address a day. If you sign up for the free Demo account that number is increased 10x.
Maxmind is another sweet site.
Keep in mind that pinpointing the exact location of someone is done with a subpoena. These locators give a general area of where the IP is being traced from. Happy hunting!
Please feel free to post any locators you use &/or information you may have on them!