Wallpaper? Nope - painted wall stencils used in combination to give the effect of wallpaper which is probably about the same effort as putting up wallpaper and is certainly less expensive. We're also counting ourselves as fans of this color combo - the orange and grey offset the girlyness of the pink in just the right way.
The image and free poodle stencil download (with instructions) come courtesy of Elle Decoration South Africa (see Holly's post at Decor8 for the link). Unless you're Amy Sedaris you probably won't want a whole wall of poodles, but you can easily find animal profiles on the web and use any animal you like (you'll get a better idea of the kind of image to look for when you see the poodle download).