You can't register yet, but that doesn't mean that you can't have any fun!
Check out the Google I/O page or the Google I/O twitter account for more info on this excellent developer's conference.
I sincerely wish that I would be able to attend this event in person, but sadly, I can't afford the trip, even though the rates are comically cheap for this conference, especially for students and teachers. How comically cheap is it? From the registration page:
Early Bird Price (until 4/16/11) $450
List Price (starting 4/17/11) $550
Academia (student, faculty) $150
BootCamp +$100 (all registration types)
Want to set up your own timer? Check out this blog post from Varun's ScratchPad for more info.