RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} ^DoCoMo.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^KDDI.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^Vodafone.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^SoftBank.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^J-PHONE.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^Mozilla.+DDIPOCKET.* [OR]
RewriteCond %{HTTP_USER_AGENT} ^Mozilla.+WILLCOM.*
RewriteRule ^$ http://www.google.com/gwt/n?u=http://www.example.com [R,L]