How to make this dynamic url static in .htaccess? 1.38 installed.

http://www.mysite.com/index.php?main_page=advanced_search_result&keyword=word1%20word2%20word3

Make the static url like: http://www.mysite.com/producttag/word1-word2-word3 or http://www.mysite.com/word1-word2-word3

The keyword maybe only have word1, or have more, like word1, word2, word3, word4......

Thanks.

Following are some rewriterule now using for other dynamic urls:

From Ultimate SEO URLs

RewriteRule ^print_page_p(.*)$ index.php?main_page=print_page&products_id=$1&%{QUERY_STRING} [L]

RewriteRule ^(.)_p(.).html$ index.php?main_page=product_info&products_id=$2&%{QUERY_STRING} [L]

RewriteRule ^(.*)_c([0-9]+)$ index.php?main_page=index&cPath=$2&%{QUERY_STRING} [L]

RewriteRule ^(.)_c([0-9]+)/(.)$ index.php?main_page=index&cPath=$2&display=$3&%{QUERY_STRING} [L]

RewriteRule ^(.)_c([0-9]+)/(.)/([-\w]*).html$ index.php?main_page=index&cPath=$2&display=$3&%{QUERY_STRING} [L]

RewriteRule ^(.*)-m-([0-9]+).html$ index.php?main_page=index&manufacturers_id=$2&%{QUERY_STRING} [L]

RewriteRule ^(.*)-pi-([0-9]+).html$ index.php?main_page=popup_image&pID=$2&%{QUERY_STRING} [L]

RewriteRule ^(.*)-pr-([0-9]+).html$ index.php?main_page=product_reviews&products_id=$2&%{QUERY_STRING} [L]

RewriteRule ^(.*)-pri-([0-9]+).html$ index.php?main_page=product_reviews_info&products_id=$2&%{QUERY_STRING} [L]

RewriteRule ^producttags/(.*)/$ index.php?main_page=producttags&letter=$1&%{QUERY_STRING} [L]

RewriteRule ^producttags/(.*)/([0-9]+).html$ index.php?main_page=producttags&letter=$1&page=$2&%{QUERY_STRING} [L]

RewriteRule ^wishlist/$ index.php?main_page=wishlist [L]

RewriteRule ^wishlist/(.*)/$ index.php?main_page=producttags&letter=$1&%{QUERY_STRING} [L]

RewriteRule ^wishlist/(.*)/([0-9]+).html$ index.php?main_page=producttags&letter=$1&page=$2&%{QUERY_STRING} [L]

For Open Operations Info Manager

RewriteRule ^(.*)-i-([0-9]+).html$ index.php?main_page=info_manager&pages_id=$2&%{QUERY_STRING} [L]

For dreamscape's News & Articles Manager

RewriteRule ^news/?$ index.php?main_page=news&%{QUERY_STRING} [L]

RewriteRule ^news/rss.xml$ index.php?main_page=news_rss&%{QUERY_STRING} [L]

RewriteRule ^news/archive/?$ index.php?main_page=news_archive&%{QUERY_STRING} [L]

RewriteRule ^news/([0-9]{4})-([0-9]{2})-([0-9]{2}).html$ index.php?main_page=news&date=$1-$2-$3&%{QUERY_STRING} [L]

RewriteRule ^news/archive/([0-9]{4})-([0-9]{2}).html$ index.php?main_page=news_archive&date=$1-$2&%{QUERY_STRING} [L]

RewriteRule ^news/(.*)-a-([0-9]+)-comments.html$ index.php?main_page=news_comments&article_id=$2&%{QUERY_STRING} [L]

RewriteRule ^news/(.*)-a-([0-9]+).html$ index.php?main_page=news_article&article_id=$2&%{QUERY_STRING} [L]