This tool will determine the country by IP address over a range of IP lists. Just enter your ip list in a text file and loat the list into the program. Press 'Dsisplay country' and you will have the IP to Country entryes. The program can do also do WhoIs requests for a specific domain. It's lightning fast and free for everyone.
Free download Ip to Country Convertor - IpToCountrySetup.msi