Rockettheme hides the php extensions etc. while you view the online demos all that is displayed in the address bar is:
demo.rockettheme.com/
How do you do this? :-\
I would really like to be able to do this for my site I think it looks far neater!!
I believe that it uses frames. The top part of the demo page is created at index.php or index.html and it links to others using html Iframe. You might view the source to see what it looks like as html.