Only people added to participate in a wave can see its contents -- all participants are shown at the top. Within a wave, all invited participants can see all content, except for private replies.
If you'd like to make the contents of a wave public, add public@a.googlewave.comas a participant. This way, you can embed the wave somewhere else using the Google Wave APIs.
If you're looking for a google wave invite, visit our blog in the near future. We will be giving away invites.
