A new web service called tp2location is providing a much needed service of finding location of any Mobile.Land line phone and it even shows that through a map with correct recognition of the Network Operator .
If the number belongs to US/ Canada then you can also retrieve more details like owner’s name, his/her street address and more , but for international users it will show your nearest City , your country and your network operator . I tried my Delhi number and it showed up correct , Nice Web app
be sure to click on international when you are searching or numbers outside US/Canada , enough of talking here is the Website TP2location
Update:- If you are looking only for USA/Canada numbers then you can get a more detailed information at Reverse Phone Detective