Here is a video showing it clearly: http://www.youtube.com/watch?v=71HTB8UXVII

And another guide (pdf): http://mars.wnec.edu/~thull/combgeom05/handout7.pdf

Link: http://www.britishorigami.info/academic/miura.php

Ted Talk (11m 35s): http://www.ted.com/talks/robert_lang_folds_way_new_origami.h...