If you're a U.S. Resident, you are now free to signup and give Office Live a shot. The Office Live Team has temporarily removed the waitlist for U.S. Residents. Here's what Matt Rolak says on the Office Live Blog:
We have dropped the requirement of a product key from our signup! The Beta is still only open to US residents for now, but ANY US resident with a valid credit card can sign up for the Beta and experience Office Live! All you need to do now is pick your product (Basics, Collaboration or Essentials) and pick your domain. So head over to www.OfficeLive.com now to get your Beta subscription started.
So go and give Office Live a shot! Matt does say that if there are a lot of signups that exceed their expectations, they may have to reinstate the waitlist - so don't hesitate if you're interested in testing Office Live!