I have the following url..
http://localhost/ci/site_controller/home
I want to remove site_controller controller
site_controller
I just found the solution in this link, it works for me: http://ellislab.com/forums/viewthread/148531/
$route['^(page1|page2|page3|page4)(/:any)?$'] = "YOURCONTROLLERNAME/$0";
Hope it helps you :)