Sony's senior VP (of marketing), Peter Dille, has stated that his company will be launching "the most aggressive marketing year in its history", this year. First with Killzone 2, then God of War 3.
Now, this does not mean that GOW3 will be launching in 2009; simply that the marketing will. However, seeing how late the company has left the push for KZ2, we wouldn't be surprised of the marketing started on launch day.
Equally interesting from Peter, is his contention that Sony "employs more people in development than Microsoft and Nintendo combined" and that this, according to Dille means that, "We'll put our exclusives up against anyone."