Congratulations on your graduation. The best way right now is to email firstname.lastname@example.org with your request. We were actually talking yesterday about how to make this a self-service item. If you have any suggestions, we would love to hear them.
I hope that you guys get it figured out. Come Spring, it'll be very interesting to see how many requests you'll get for switching the email address. So many graduates! Personally, I'd just like to see an option for editing the email address when you click on "Edit Profile & Privacy". As a user, it was the first place I went to look. I was just expecting to find a button for editing my email address and then receiving a confirmation message in my new email inbox. I'm sure, however, that you guys will find a great system for this. It's great seeing the website flourish!