Load pages using URL variables

[eluser]zend[/eluser]
Hello

I need help for dinamyc pages.
I want you all to my page rendered in one div tag. $page (all in one)
Like this :
http://woork.blogspot.com/2007/10/load-p...d-php.html
Without a load on the other.

Clicking on a link replace the old page in a new page.

How could this be done in codeigniter?