perl-IP-Country -- Fast lookup of country codes from IP addresses
http://search.cpan.org/dist/IP-Country/
IP::Country allows fast lookups of IP addresses and their corresponding
countries based on available regional NIC data. Although the country
of assignment will probably be the country associated with a large ISP
rather than the client herself, this is probably good enough for most
log analysis applications, and under test has proved to be as accurate
as reverse-DNS and WHOIS lookup.