this can also be said as tracing a person by knowing his/her Ip address so lets begin the tutorial.
1st step:
First of all you need to make the person online or you you need to chat with him via any social networking site
like Facebook,G-mail,Orkut or via any messenger like yahoo messenger, Facebook messenger, Skype...etc.you type your message like hi or hello and wait till you get reply from another side.
2nd step :
after getting response from your friend
now you need open command prompt or cmd and then type this command netstat -a
if you are using any messenger then better go for this dos command netstat -nbt
Now carefully watch the ip address and get the victim's ip address...
After knowing the ip address you can easily trace the location of the victim's computer.
Go to this site.http://www.whatismyipaddress.com/ Or
http://www.ip-address.org/ to locate the correct location
You can compare the User details and the IP details and traceout user's IP adress.