This video tutorial by photoshopuniverse shows you how to create a postage stamp in Photoshop. First take a suitable image and decide the shape of the stamp. Corp the image to suit the shape of the stamp by selecting the area and choosing corp and increase the canvas size as shown in order to create the perforated cutout. Transform the image into a regular layer and once again increase the canvas size to create a back ground with an appropriate color as shown. Add a layer mask, chose the brush tool, go to brush options and change the brush tip shape, diameter, spacing, hardness and other parameters as required and draw the edge as shown. Add some suitable text and now your stamp is ready for use.