This is a video of a dinosaur on the loose in the LA Museum of Natural History. The overall effect is pretty compelling. The movements are very well controlled.
(:flash http://www.vimeo.com/moogaloop.swf?clip_id=1316102&server=www.vimeo.com&show_title=1&show_byline=1&show_portrait=0&color=&fullscreen=1 width=400 height=267:)

Not suprisingly, it's not a 'real' robot. There's a pupeteer inside controlling the action, with a lot of motorized assistance. What is suprising is that the on you saw above is the small version. Check out this video showing their construction, and a few of the larger models.
(:flash http://www.youtube.com/v/OtfMIiinJso width=425 height=344:)