You can easily create a composition like this from three similar shots using layer masks in Photoshop. Basically, you set up a tripod, take a few single shots of you in different positions and compose the whole thing in Photoshop, using layers and masks...
First, select one of the shots as the main layer of the composition
open the second shot, select all (menu > select > all) and copy (menu > edit > copy)
paste (menu > edit > paste) into the first image, note the additional layer in the first image
create a layer mask by clicking on the marked icon in the layer palette
Photoshop layer masks part 2 >>
