Something

        # Redirect from *.domain.* to *.domain.com
        RewriteEngine On
        RewriteCond %{HTTP_HOST}               !^$
        RewriteCond %{HTTP_HOST}               !domain\.com$
	RewriteCond %{HTTP_HOST}	(.*)\.domain\.
        RewriteRule (.*)     http://%1.domain.com$1     [L,R]