This is one pop-up window in WordPress:

I used the code as below, but can’t get the pop up window as above:
window.open(‘popup.php’,’popup window’,
‘height=300, width=300, top=180, left=300, toolbar=no, menubar=no, scrollbars=no, resizable=yes,location=no, status=no,titlebar=no,channelmode=no’);

Added:

I got some answer from linkedin.com. It is built by lightbox. I think about uploading, it uses AJAX.

WordPress 3.0 uses thickbox, but its author has stopped updating it. So, I will try fancybox.

some useful links:

Updated: Which Lightbox is Right for You? 
Rounding Up the Top 10 jQuery Lightbox Scripts 
http://fancybox.net/