As usual, the whole thing is rather cryptic. From the "blueprint" graphic and text, it sounds like the event will be limited to an overview (but not a release) of iPhone OS 3.0. Perhaps we'll learn a bit about any changes to the SDK as well.
What would you like to see? Copy and paste, for sure. Push notifications for 3rd party apps next. Anything else?
Finally, we don't know who will be doing the talking. Typically, we just assumed it would be Steve.