$PATH_INFO is your friend when it comes to creating clean URLS. Take for example this URL:

http://www.company.com/products/routers

If the Apache configuration contains this block:

<Location "/products">
  ForceType application/x-httpd-php
</Location>

Then all you have to do is create a PHP script in your DOCUMENT_ROOT named 'products' and you can use the $PATH_INFO variable which will contain the string, '/routers', to make a DB query.