As iPod’s video capability continues to gain credibility in the marketplace, Ty Burr wonders where movies are headed. “This could be insanity. Or it could be the way our kids may someday watch movies: if not on an iPod, then on a similar portable device bigger than a postage stamp and smaller than a kitchen television. Rend your garments and wail over the death of the big-screen experience all you want, movies are slowly and unstoppably becoming disassociated from the theaters in which we’ve been seeing them for more than a century.”