Custom Configuration File For Application

[eluser]smatakajr[/eluser]
Hi,

I come from an Oscommerce background.. so im used to the whole application_top
require to set config directives. In making the change to CI which i must
say is pretty sweet and extendable im just getting used to the whole
3 step MVC format even though my prior code was indeed heavily encapsilated
anyway..

Is there a way in CI to include a application_top or config.php file that
will sit on the top GLOBALY so i dont have to load it in each model or controller?

I see the application/config/ and the autoload so im guessing my best bet is
to make a plugin or helper and add it to the autoload. Will this achive the same
effect as

include('config.php');
<?php ...code.. ?>

Sitewide?

Thanks alot
Rick