When SCEA released God of War II last year, the game's instruction manual teased the soon to be released PSP entry, God of War: Chains of Olympus. Now it's the PSP's turn to toy with your emotions, as the manual for the on-the-go Kratos quest fires back with a tease of the PlayStation 3 chapter. IGN has photographic evidence of the PS3 sequel teaser ad which opts not to put a release window on the thing, merely announcing that it's "coming soon."
Considering rumours are pointing to a 2009 ship date for God of War III and Sony has a habit of showing these games a year (or more) in advance, we'd say that if you want a Kratos fix in 2008, it's probably going to be on UMD.
God of War III Ad [IGN]