The new Xbox 360 update that adds support for Twitter, Facebook, the Zune store, and Last.fm is now live. You can get the update simply by logging into Live on your 360. If you want to read more about the new stuff you can do so at Xbox.com.
Even if you are not currently a Gold member on Live you can still have a peak at the new features on the upcoming free weekend.
While I can't say I care about having my Facebook tied to my Xbox, and I flat out despise Twitter, the Last.fm and Zune store both look interesting. Though one must ask how much Microsoft expects us to use the Zune store given the 360s antiquated and overpriced hard drive options...