There's a preview of Left 4 Dead on IGN looking at both Co-op and Versus modes and another on Shacknews focusing on Versus mode, IGN specifies they were playing the Xbox 360 edition. Both articles go into various aspects of gameplay and also offer movies, there is a ShakyCam clip on Shack and several direct-feed clips on IGN. Shacknews also has some screenshots, and a confirmation that plans for a demo in early November have not changed in the last six days (story, story, and story).