Is this to block certain countries from your site? If so, and if you have root access, you could compile Apache including the mod_geoip module to help filter this, instead of clogging .htaccess or firewall deny lists and such, potentially causing a high load on the server.
If you want to do some kind of geo targeting, take a look at MaxMind's GeoLite Country (it's free): http://www.maxmind.com/app/geolitecountry