Last month, an event was hosted by the Google Wave team called Google Wave Federation Day, which was described as an inaugural event for people looking to get involved by providing their own wave services.
At the event, Google discussed the protocol and system architecture behind Google Wave, and talked about how they need to get lots of developers working on it, because it is such a huge vision. That vision is for there to be many Google Wave providers, because as Google says, it won’t be complete without non-Google Google Wave providers.