It would just need a comprehensive player stat index where you can click on the playername to see location, (and activity percentage, time taken per move, games won, games played, ranking, score, favourite continent etc.)
The other option would be a fairly simple google maps integration (i.e. like http://www.frappr.com/
) which wouldn't even take up bandwidth because it is offsite.
the other option would be a simple "area specific" flag for each game and then just force people to fill in a timezone in their profile.
many many ways to do it.