Man, i can't wait for that game. Konami is being real stingy with details. One thing i do remember, though, is that the main character is snake. When MGS2 came out, and people found out you weren't snake the whole time(I hated raiden), they got pretty upset. I guess the outcry was so bad, konami said "fine, in the next game, you'll be snake" when they announced that 3 was in developement.
More details at this years E3. and i guess Konami is hoping for a simultaneous japanese/american christmas release this year...don't know what happened with that, though.