While the teaser site hasn't provided much information regarding Rare's next entry in the Banjo-Kazooieverse for the Xbox 360, Rare community manager George Kelion has proved a veritable wellspring of information. Posting on the NeoGAF forum topic regarding the teaser site, Kelion says that the game should be coming out in time for Christmas this year.
The game is scheduled for a Holidays 2008 release - barring the coming of the four horsemen of the apocalypse, you should be playing Banjo 3 before the end of the year (providing you buy the game, that is).
Further assuaging forum-goers' fears, George promises the game isn't being developed for children, and that the game is safely in the hands of lead designer and Banjo-Kazooie creator Gregg Mayles. Finally, in response to the rather crappy-looking Banjo pic on the teaser site..
I really wouldn't base your ultimate judgments of the final Banjo model from what you've glimpsed on the teaser site if I were you - all shall be revealed in due course, not that long to wait now...