Here's the official statement by the Commission on Presidential Debates:

This is the official CPD statement I got from the website of the University of Mississippi [Note how they say that the public will be "well-served" by having the debate]:

Oxford, Mississippi: September 24, 2008 -- “The Commission on Presidential Debates (CPD) is moving forward with its plan for the first presidential debate at the University of Mississippi in Oxford, Miss. this Friday, September 26. The plans for this forum have been underway for more than a year and a half.

"The CPD’s mission is to provide a forum in which the American public has an opportunity to hear the leading candidates for the president of the United States debate the critical issues facing the nation. We believe the public will be well served by having all of the debates go forward as scheduled.”