/modules.php?name=News&file=article&sid=600

/news/story/600/

RewriteEngine on
RewriteCond %{QUERY_STRING} ^name=News&file=([a-z_]+)&sid=([0-9]+)
RewriteRule ^modules.php /news/story/%2/ [R=301,L]

RewriteEngine on
RewriteCond %{QUERY_STRING} sid=([0-9]+)
RewriteRule ^/modules.php /news/story/%1/? [R=301,L]