Script Help ?

Anyone know where to find the script where,
You enter a website and automatically a popup appears.

I need this because I want to put the radio player in the popup as im using joomla..

I think there was a script like this on:
www.dynamicdrive.com

http://javascript.internet.com/gener...up-window.html

Both are right.
But Lucas is righter :P

Thanks :D