Instructions to make "slide togethers" are here:
http://www.georgehart.com/virtual-polyhedra/slide-togethers.html
The instructions from here have been used to make this worksheet which allows templates to be made for different shapes of rectangles:
http://www.flickr.com/photos/fdecomite/3616078966/
If you load this file into GeoGebra then you can export to different formats (eg SVG, PNG) and also insert your own images.
