Seeing how 2006's WWDC Keynote was only 1.5 hours, the announcement that Apple's blocking off 3 hours makes us smell what the Rock is cooking (a.k.a., lift our eyebrows in a comical yet masculine way). What do we think's going to happen? Well, we think Apple will formally unveil the iPhone features we didn't see and then talk about it for an hour and a half, filling in whatever missing features that weren't covered in January. Then, they'll show developer tools so people can get in on the action of getting stuff onto the iPhone.
After that, they'll probably transition to Leopard talk, giving up some more features there as well, and showing new things developers can do.
Of course, we pulled all of this out of our ass, but it seems likely, no?
Update: We just spoke to Apple and the Keynote's actually only 1.5 hours. Ignore everything we said above.
Brilliant photoshop again by Jesus Diaz