I've seen this done both ways, but out of courtesy, the PM should be the first recipient of the communication. The project communication plan should spell out in detail who communicates what to whom and when. By allowing the project manager to perform the communication, the project sponsor is helping the PM become the established authority on the project.
If it is early enough in the initiation and planning cycle, then the team would not even be in existence, if you are following the PMBOK Guide processes. The PM receives the charter and then heads up that project with the team.