This update became available to everyone on August 11th, 2009. This gives you a look at all the new features you should expect to see, including the Avatar Marketplace, Games on Demand, new Netflix features, Movie Parties, and more. This is your definitive walkthrough of the next Xbox 360 dashboard update.
Xbox 360 August 2009 Dashboard Update Definitive Walkthrough (http://www.youtube.com/watch?v=fA6Ca2MdFMU#ws-lq-lq2-hq-vhq-hd)