Don't just block them, redirect them to something that will at least give you a chance at some extra money. Try
Password By Phone.
Install a database and use .htaccess:
http://www.maxmind.com/app/mod_geoip (the free one is pretty decent, the paid one obviously a bit better)
Code:
GeoIPEnable On
GeoIPDBFile /path/to/GeoIP.dat
RewriteEngine on
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^CN$
RewriteRule ^(.*)$ http://www.chinese.url [L]
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^RU$
RewriteRule ^(.*)$ http://www.russian.url [L]
etc...