AP Photo/Alex Brandon
Democratic presidential candidate, Sen. Barack Obama, D-Ill., gives his acceptance speech at the Democratic National Convention at Invesco Field at Mile High in Denver, Thursday, Aug. 28, 2008.
AP Photo/Ron Edmonds
Democratic presidential nominee, Sen. Barack Obama, D-Ill., gives his acceptance speech at the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Jae C. Hong
Democratic presidential nominee, Sen. Barack Obama, D-Ill., delivers his speech during the final session of the Democratic National Convention at Invesco Field in Denver, Thursday, Aug. 28, 2008.
AP Photo/Chris Carlson
Michelle Obama, wife of Democratic presidential nominee, Sen. Barack Obama, D-Ill., and daughters, Malia, left, and Sasha are seen on the final night of the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Alex Brandon
Democratic presidential candidate, Sen. Barack Obama, D-Ill., hugs his wife, Michelle Obama, after giving his acceptance speech at the Democratic National Convention at Invesco Field at Mile High in Denver Thursday, Aug. 28, 2008.
AP Photo/Jack Dempsey
Fireworks explode over Invesco Field at the end of the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Jae C. Hong
Democratic presidential nominee, Sen. Barack Obama, D-Ill., waves with his daughter Sasha, 7, after his speech during the final session of the Democratic National Convention at Invesco Field in Denver, Thursday, Aug. 28, 2008.
AP Photo/Jae C. Hong
Democratic presidential nominee, Sen. Barack Obama, D-Ill., hugs democratic vice presidential nominee Sen. Joe Biden, D-Del., as Obama's wife Michelle, far left, hugs Biden's wife Jill after Obama's speech during the final session of the Democratic National Convention at Invesco Field in Denver, Thursday, Aug. 28, 2008.
AP Photo/Chris Carlson
Democratic vice presidential nominee Sen. Joe Biden, D-Del., acknowledges the crowd at the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Charlie Neibergall
Former Vice President Al Gore waves after addressing the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Charlie Neibergall
Musicians will.i.am., left, and John Legend perform "Yes We Can" on the final day of the Democratic National Convention at Invesco Field in Denver, Thursday, Aug. 28, 2008.
AP Photo/Jeff Chiu
Mark Reese, 13, from Golden, Colo., waves a flag before Democratic presidential nominee Barack Obama, D-Ill., gives his speech during the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Alex Brandon
Democratic presidential candidate, Sen. Barack Obama, D-Ill., speaks after making a surprise visit to the Illinois delegation luncheon in Denver ahead of his much-anticipated speech as the Democratic National Convention comes to a close, Thursday, Aug. 28, 2008.
AP Photo/Alex Brandon
Democratic presidential candidate, Sen. Barack Obama, D-Ill., smiles as he makes a surprise visit to the Illinois delegation women's luncheon in Denver, Thursday, Aug. 28, 2008.
AP Photo/Peter Fredin
A woman holds a pin with Martin Luther King on it at the Democratic National Convention in Denver, Thursday, Aug. 28, 2008. Barack Obama will accept the Democrats' nomination, the first black person to claim such a prize, on the 45th anniversary of Martin Luther King Jr.'s historic "I Have a Dream" speech. The Democrats officially made Obama their presidential nominee on Wednesday.
AP Photo/Ron Edmonds
Sheryl Crow rehearses for her performance later at the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.
AP Photo/Ron Edmonds
Former Vice President Al Gore looks over the podium at Invesco Field at Mile High at the Democratic National Convention in Denver, Thursday, Aug. 28, 2008, prior to his scheduled speech.
AP Photo/Ted S. Warren
Democratic vice presidential candidate Sen. Joe Biden, D-Del., takes a photo of himself with an unidentified Army National Guardswoman Thursday, Aug. 28, 2008, at Invesco Field in Denver. The troops, from Georgia and Nebraska, were in Denver to provide medical and rescue assistance to local and national authorities during the Democratic National Convention.
AP Photo/Jae C. Hong
Olympic gold medalist in gymnastics Shawn Johnson waves during a rehearsal for the final night of the Democratic National Convention at Invesco Field in Denver, Thursday, Aug. 28, 2008.
AP Photo/Charles Dharapak
Singer Stevie Wonder rehearses on stage at Invesco Field at the Democratic National Convention in Denver, Thursday, Aug. 28, 2008.