Major Nelson has come out and said
that those wanting to preview some new features coming to Xbox LIVE can now sign up
. They're looking for a lot of people so there's a good chance you'll get in he says. The features you'll be previewing will be the 1080p streaming, Facebook, and Twitter integration.
Out of the three, I'd probably only use the 1080p movie streaming. I prefer to do my Facebook or Twitter via my computer or my mobile phone. That's not to say it's not going to be useful for some folks. It's just I was never excited about those two when they were announced.