Help w/ javascript/css

hey there everyone, i was making a site and wanted to make a popup on mouseovers like on ask.com (where you mouse over the binoculars after a search, it pops up a screenshot of the site)

how is this effect implemented? through css or js? i was wondering if anyone had any resources on this? anything would be helpful thanks!

edit: screenshot >> http://img148.imageshack.us/img148/7938/untitled22bx.jpg

Probably JS… but I don’t see the effect.

i attached a screenshot for the effect

Oh, I’d guess a bit of both. JS for the grabbing of the image and adding it onMouseOver, and CSS for the tooltip bubble, and the padding of the image.