The hubbub begins June 14 with a Microsoft Natal party thing, but it officially begins June 16. Most major press conferences are June 15.
I'd say my opinions, predictions, and all that jazz here, but we're working on a big E3 prediction feature at PixlBit, so I'm saving a lot of my ideas, even the crazy, for that, so I'll just make one guess for each of the numbers:
1: PSP2 will be a PSP with two sticks, better graphics, and a touchscreen, but nothing really new or innovative beyond what the PSP already does.
2: A new Smash Bros, with the promise of balance and downloadable gameplay/character tweaks. 2D Metroid with, unbelievable multiplayer functionality that fits the Metroid series perfectly some how.
3: Natal being an innovative, easy to use success. Kid Icarus anything.