PHP Content Management System

I am fairly new to PHP.

Is it possible to build a Content Management System using PHP.

Is there free packages out there I could use to management my website, if so what would anyone recommend? Is it then easy to add to my site?

I would only want the content to be managed allowing them only t use certain styles. The navigation would not be editable.

Any comments would be welcomed.

Thanks
Tuscan

There are many good CMSs on the Internet such as Joomla

Once upon a time there was phpNuke but I don't know if that's still around.

I've been a growing fan of drupal

Also a +1 for the Joomla response.

phpBB can also be leveraged as CMS depending on what you really want.

I am a Chinese, seldom touching with the foreign CMS