After months of leaked testing images and rumors, Amazon's finally updated its Video on Demand service to HD. 500 shows and movies will be available in high-def to start, and the service is expanding to include Panasonic VIERACast TVs in addition to Series3 TiVos, the Roku Video Player, and the Sony Bravia Internet Link. Head to head with the Apple TV, the only downside we see is that audio is stereo-only and not 5.1, but
