Microsoft did this back in July for the early Fall dashboard update. Now, they’re launching the same program for the upcoming dashboard. While no official date has been set for the update, it should be pushed out in the next few weeks and is set to include Twitter, Facebook, Ping.fm and Zune Marketplace features.
Click here to sign up for the program. (Console serial # and ID required)
[...] Microsoft having offered several preview programs in the past, it’s unclear as to whether this program will be open to a small batch of users, or a larger user [...]