What you need is to use Apache's
mod_rewrite to redirect (rewrite) requests for
domain.com/reviews/(whatever)
to
domain.com/(whatever) and send the 301 status
So you would add something like this on your .htaccess file
Code:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^reviews/(.*)$ http://domain.com/$1 [R=301,L]
</IfModule>
Oops, didn't see the .php post issue until later. Code I posted wouldn't work under those circumstances.
You might want to try this plugin
http://wordpress.org/plugins/rewrite/