Geotagging

Is there a way to have anonymous votes be stored in de DB by country code?
Every vote is stored with the voters ip (i think). So it should in theory be possible to retrieve the country code (for example by using the ipinfodb api see: ipinfodb.com/ip_location_api.php).
My plan is to have registerd users be able to plot voting behavior on a world map by using google's geomap api (see: code.google.com/apis/visualization/documentation/gallery/geomap.html)
I think a can do the coding myself. However it would be much easier if someone could point me in the right direction. Which php(s) file should be altered (on clicking: VOTE).
Of course one can also plot the data on a worldmap without having the country code data stored in the database but when having a poll with a lot of votes this could take a lot of time (ipinfodb alows for 1 ip info per second)
Regards,
Sake (Globalpoll)