Alternate Delegates (Super Delegates) can't vote until the Convention. All 750 of them could cast their ballot for either Hillary or Obama.  There's no way to know who will be the nominee until the Convention seats Michigan and Florida and the Alternate Delegates cast their vote at that time.

Is Jimmy Carter Letting Democratic Voters Down??
Posted on April 15, 2008 by GRL

On Monday (April 14) I caught a brief comment by Jimmy Carter about the Nepal elections on the BBC World Service. Carter, who was in Nepal to monitor the polling, said that whatever problems occurred had "paled" compared to the overall success of the vote. (Unfortunately, the audio report is no longer available.)

In a report issued on April 15 entitled Trip Report by Former U.S. President Jimmy Carter to Nepal: April 6-14, 2008, Carter wrote in great detail about all the efforts made to ensure a free and fair election.

   <We have maintained a staff of long-term election observers for more than fifteen months. They have visited all 75 districts and had an opportunity to become familiar with the entire nation and its various and conflicting political factions.</p>

   After our arrival from Atlanta, we joined Dr. John Hardman and began receiving extensive briefings from former U.S Ambassador Peter Burleigh, David Pottie, Darren Nance, Sarah Levit-Shore, and others. Most of our 60 international observers, from 21 nations, had been deployed to the more remote areas by helicopter, all-terrain vehicles, and by foot. My co-chairman was Dr. Surakiart Sathirathai, former deputy prime minister of Thailand, who was a key partner and essential to the mission's success. Our team was joined by international observers from the European Union, Asian Network for Free Elections (ANFREL), and by several thousand domestic observers. ...

   On election day we visited as many polling sites as possible in the valley that surrounds Kathmandu and found the election commission's procedures were being largely followed. There were long and separate lines of men and women in a celebratory mood, the total turnout being above 60 percent. Despite some problems, our observers throughout the nation found the same situation among a total of 400 sites visited. Ballot boxes were required to be delivered to 75 central locations for counting, and we observed a number of these procedures.>

Impressive, no?