Apparently within the last three hours:
“She is not seeking the vice presidency, and no one speaks for her but her,” communications director Howard Wolfson said. “The choice here is Senator Obama’s and his alone.”
In an e-mail to supporters, the New York senator said she “will be speaking on Saturday about how together we can rally the party behind Senator Obama. The stakes are too high and the task before us too important to do otherwise.”
Clinton expressed the same sentiment in a conference call with 40 members of her national finance committee, whom she urged to begin raising money for Obama and for the Democratic National Committee.
This isn't really a surprise, although its quick arrival is probably a pleasant one.