I implemented the header effect of those flying black polaroids on kremalicious.com following the original idea by the folks of clearleft on their silverback teaser page

This effect drew much attention in the webdesign community and meanwhile there are some great articles about this effect. Over at thinkvitamin is a detailed explanation of the effect. Paul Annett from clearleft gives an in-depth-view how they created the parallax effect on their silverback teaser page.

A more common explanation gives Chris Coyier over at css-tricks.com. He uses three star layers to make a cool space-effect.