To install the GeoIP C library, go to
http://www.maxmind.com/app/c
Note that Geo::IP 1.13 requires GeoIP C 1.1.2 or higher
To install the Perl XS wrapper, run
perl Makefile.PL
make
make test
make install
(If you get a "libGeoIP.so.1: cannot open shared object No such file or
directory" error, add /usr/local/lib to /etc/ld.so.conf then run
/sbin/ldconfig /etc/ld.so.conf )