This is a great site to start with: http://www.frommers.com/destinations/beijing/
Together with the last time I was in Beijing I have seen most of the major sights like
Forbidden City
Summer palace
Tiananmen Square
Ming Tombs
Great Wall at Badaling
Lama Temple
Temple of Heaven
University of Beijing
Renmin University
So today I am going to go to the Zoo and do some Shopping at the end of day. Tomorrow I will go see Mao's mummified body in Tiananmen Square and the Great hall of the people.
I am boarding a train to Shanghai tomorrow night at 7:00. I will get to Shanghai the next day at 8:00AM.