Aye, Maxmind's
http://www.maxmind.com/app/mod_geoip
Install the database, then just this to your .htaccess
GeoIPEnable On
GeoIPDBFile /path/to/GeoIP.dat
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} !^US$
RewriteRule ^(.*)$
http://yourinternationaldestination.here [R,L]