On June 25, 2001, President Bush nominated John H. Marburger III to the position of Director of the Office of Science and Technology. Colloquially, Marburger was the president's science advisor and he wasn't even confirmed until October 2001. This came nine months after Bush was sworn into office. It spoke volumes on where Bush stood on the importance of science in his administration, and the past eight years has shown that science took a backseat to policy in nearly every area.
President-elect Obama is currently undergoing the transition process. Although the individual nominated for the position is much more important than when that nomination occurs, having a science advisor in place before inauguration will send a signal on the importance of science and technology in the new president's agenda.