Google is rolling out more than 100,000 invitations to preview Google Wave to: “developers who’ve been active in the developer preview started back in June, first users who signed up and offered to give feedback on wave.google.com, and select customers of Google Apps”. Invites’ll be asked to nominate people they know also to receive early invitation. It has been great fun to see the cool extensions already built or being planned and incredibly instructive to get their help planning the future of our APIs. Watch students collaboratively write stories in Google Wave about an imaginary trip around the world at Google's Sydney office.
More info: Developers blog