How I set mine up was like this:
php_flag session.use_trans_sid off
Options +FollowSymLinks
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.*) - [L]
RewriteRule !\.(gif|jpg|png|css|php|swf|inc|ico|js|cgi|wmv|mpg|mpeg|avi|mp3|midi|rar|zip|scr|phps|txt)$ /process/index.php
ErrorDocument 404 /missing.php
Basically what happens is if it is a real directory, it takes u to that directory. No questions asked.
If the url you are requesting is not a real directory and it is not a file then redirect it to process.php for it to be handled.
In the process.php you can handle the extra slash how you want to.
Questiosn feel free to email me if you like. frost110 -at- gmail -dot- com
--FrosT