Right now you can go and sign-up for the preview to the newest Xbox 360 dashboard update. This update will feature the integration of both Facebook and Twitter to your gaming experience.
All you need to do is fill out the survey and hope that you are one of the lucky few (hundred or thousand) chosen to test it out. Email will be sent out next week letting you that Microsoft has chosen you and when you can expect to download the update.
The official update should happen sometime around November 17th (at least in the UK).
Sign Up Here
[Source: Major Nelson's Blog]