RewriteEngine on 

RewriteBase /

RewriteRule ^/?(index|guestbook|online)\.html$ index\.php [L]

RewriteRule ^/?(index|guestbook|online)-([0-9]+).html$ index\.php\?p=$2 [L]

RewriteRule ^/?([a-z0-9]+)_([0-9]+).html$ index\.php\?act=$1&id=$2 [L]

RewriteRule ^/?([a-z0-9]+)-([0-9]+).html$ index\.php\?act=$1&cid=$2 [L]

RewriteRule ^/?([a-z0-9]+)-([0-9]+)-([0-9]+).html$ index\.php\?act=$1&cid=$2&p=$3 [L]