AT&T will be offering a free preview of the U-verse U450 channel package during the Thanksgiving holiday that includes premium Cinemax, Encore, HBO, Showtime, and Starz movie channels. The HD versions of those channels will also be accessible during the preview. Base-priced at $91 per month, the U-verse package offers up to 430 channels including Local Channels, Music Channels, the Premium Movie Package, and the Premium Sports Package. The free preview will begin Thursday, Nov. 22 and run through Sunday, Nov. 25.