The transparent laptop screen you see on the right is no Photoshop trick, but a rather ancient (by internet standards) optical illusion.
The trick is simple; take an image of the immediate background of your laptop monitor, make sure the pixel dimensions of the image match the physical dimensions of the background, and make some minor color adjustments to make it look transparent. For more comprehensive instructions, use this article.
The effect, as you can see, is quite stunning. Check out this Flickr Set for more examples.