From what I understand, Sony is dividing up it's announcements between E3, Leipzig, and TGS.
At E3 they announced new projects from SCEA (God of War III, MAG), at Leipzig, they are showing off new SCEE stuff (Heavy Rain will be re-unveiled, as well as other announcements), and at TGS will come the SCEI stuff (presumably Team ICO, among other things).
Sony is the only one of the big three at Leipzig this year, and they have a whole conference that will be starting in six hours. They've promised 12 new announcements for the show. :)
Nintendo I'm far less sure about. They'll probably have some presence at TGS, but I think they'll show the big stuff whenever they're ready, most likely at an event of their own.
I expect Zelda to surface at E309, however, with a Holiday '09 release date.







