server {
listen 80;
server_name ~^(?<subdomain>[a-z0-9\-]*?)\.(?<domain>[a-z0-9\-]*?\.(?:com|cn|net|org|gov|info|la|cc|co|hk)(?:\.(?:cn|jp))?)$;
root /www/webpub/$web_path;
index index.html index.htm index.php;
set $web_path $domain/$subdomain;

if ($subdomain = phpmyadmin) {
set $web_path phpmyadmin;
}

access_log /www/wwwlogs/$subdomain.$domain.log combined;

location ~ ^/.+\.php {
fastcgi_index index.php;
fastcgi_split_path_info ^(.+\.php)(.*)$;
fastcgi_param SCRIPT_FILENAME $request_filename;
fastcgi_param PATH_INFO $fastcgi_path_info;
fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info;
include fastcgi_params;
fastcgi_pass unix:/dev/shm/php-cgi.sock;
}

location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$ {
expires 30d;
}

location ~ .*\.(js|css)?$ {
expires 1h;
}
}

智能配置，一个conf搞定所有站，已知问题：对没加www.的域名，如xxx.com无法访问，可以通过域名解析跳转到带www的域名。

几点说明：
（1）/www/webpub与/www/wwwlogs，网站目录与网站日志目录，改成你自己的。
（2）phpmyadmin为所有站点共用目录，解析二级域名或者本地改hosts指向phpmyadmin.xxx.com即可用phpmyadmin管理数据库。
（3）不支持不带www的域名访问，高手请完善下正则判断