We are going to take this with a grain of salt, but the French website JeuxActu.com claims they have confirmation from Sony at IDEF (Interactive & Digital Entertainment Festival) over in Cannes that God of War 3 will make "an appearance in high-definition" at next month's E3. The site then speculates the chance of any sort of gameplay being shown is almost non-existent.
The first appearance of Kratos on the PS3 would be extremely exciting, even if it is just a teaser video. We'll find out when E3 rolls around next month!
[Thanks, Noshino, Kspraydad and everyone else who sent this in!]