The registration functionality is current down. The support team is working furiously to get it back up and running, but I know there have been a bunch of people trying to register for the Intel Developer Zone in order to submit their entry.
At this time, I think it's only fair that we to extend the deadline to 12 noon, Pacific time on June 3. I'll update here if further deadline extensions are required, but I've got my fingers crossed that the registration gets back up.
Please note, if you've previously registered for the Intel Developer Zone, you should be able to login and submit, it's just new registrations that are having problems, but I do want to give everyone a fair chance.